EA043521B1 - ROTATING FILTER AND RELATED FILTRATION METHOD - Google Patents

Description

The present invention relates to a rotary filter and associated filtration method, particularly the type used in an industrial plant for liquid/solid separation under vacuum or pressure conditions. This type of filter is usually used to filter a liquid filled with solid particles, called slurry, formed, for example, during ore processing, crystallization, etc.

In many industries, the separation of solids from suspension is accomplished by filtration, preferably using decanting techniques, which require large volume units and excessively long decanting times, or preferably using centrifugation techniques, which do not achieve the required degree of separation and are expensive. for the necessary energy resources and maintenance.

The basic principle of filtration is to force a suspension through a filter medium whose porosity allows the passage of liquid but prevents the penetration of solid particles. The liquid obtained as a result of filtration is usually called filtrate. As the filtrate flows through the filter media, a layer of solids accumulates on the surface of said filter media. As this layer of solid particles, usually called sediment, grows, it increasingly resists the passage of the liquid phase. Thus, from time to time it may be necessary to remove said sediment when it is as thin as possible. The sediment is removed through an operation called descaling. In the case of fine sediments, effective sediment removal involves flushing away the sediments by spraying a fluid. This method of removing sediment is called release.

In the case of a rotating disk filter, for example, the filter includes a tank, called a trough, containing the suspension to be filtered, and a main horizontal shaft equipped with at least two flow paths, and at least one disk containing at least two independent filter sectors, each of which is equipped with a filter medium and which are distributed evenly around the shaft. The inner side of each filter sector is in connection with the flow line. The disk is partially immersed in the suspension so that the filter sectors are saturated with said suspension during part of their movement during the rotation of the shaft.

In the case of a pressure rotating disc filter, the discs are placed in a pressurized casing, which typically forces the slurry through the filter media to the flow lines. Filter cakes are formed on the media of the filter sectors. When the filter sectors come out of suspension during their movement, said filter cakes are subject to torsion, which subsequently facilitates their removal.

Currently, in order to carry out said sediment removal by release, it is necessary to empty the trough containing the suspension in advance. The release thus leads to downtime, which degrades the filter performance the more the shorter the fine sediment formation time.

The object of the present invention is to provide a rotary filter and associated filtration method that allows fine sediments to be handled by removing them by release without the need to empty the slurry containing trough, thereby providing maximum filtration performance.

This object is achieved in accordance with the present invention by means of a rotating filter for separating a suspension into liquid/solids, including a trough containing the suspension, a device for spraying a fluid for release and at least one disk which is non-rotatably connected to the main shaft, wherein each disk is partially immersed in the suspension and each disk includes a plurality of filter sectors, wherein each filter sector includes a structural element that is covered with a filter medium, and a passage for connecting said sector to a flow line located along the main shaft, and characterized in that each disk includes a first series of at least one filter sector, which is separated from a second series of at least one filter sector by two non-filter zones;

the main shaft includes a first flow line that communicates with a first series of at least one filter sector of each disk, and a second flow line that communicates with a second series of at least one filter sector of each disk;

said rotating filter includes comb teeth that are located above the slurry level on each side of each disk, the main shaft being configured to be in at least a first angular position in which a first series of at least one filter sector of each disk is placed under the comb teeth, being impregnated with the suspension to be filtered, and wherein a second series of at least one filter sector of each disk is placed over the comb teeth, each non-filtering zone adjacent to one comb tooth on each of its surfaces;

- 1 043521 second angular position, in which the second series of at least one filter sector of each disk is placed under the teeth of the combs, impregnated with the suspension to be filtered, and in which the first series of at least one filter sector of each disk is placed above the teeth of the combs, wherein each non-filtering zone is adjacent to one comb tooth on each of its surfaces to provide release on a series of at least one filter sector of each disk placed over the comb teeth, while filtration of the suspension continues on another series of at least one filter sector each disc placed under the teeth of the combs.

In accordance with other advantageous features of the present invention, the rotary filter includes at least one seal that is located between each non-filter zone and an adjacent comb tooth when the main shaft is in a first angular position and when the main shaft is in a second angular position;

each seal includes a retractable portion that is capable of switching between an extended state in which it creates intimate contact between the non-filter zone and an adjacent ridge tooth, and a retracted state in which there is no longer intimate contact between the non-filter zone and the adjacent ridge tooth;

each seal includes at least one elastically deformable part;

each seal is located on a non-filtering zone;

each non-filter zone includes a disk sector, called a non-filter sector, which is located between the filter sector of the first series and the filter sector of the second series;

each non-filter sector includes at least one pressurized fluid inlet tube that is connected to a supply path that is disposed along the main shaft so as to allow each seal to be extended by pumping and each seal to be retracted by pumping;

each seal is a diaphragm which is attached to the non-filtering sector by its peripheral edges and which includes a movable main wall which is connected to the peripheral edges by a wedge-shaped connecting part;

the teeth of the combs are attached to the edges of the groove;

each tooth of the comb is inclined downward from the main shaft to the outer side to facilitate the flow to the outer side of the trough of portions of slurry formed by the mixture of fluid used in the release of filter cakes removed from the filter sectors;

the main shaft is equipped with a first flow type valve that allows the first flow line to be closed when the first series of at least one filter sector of each disk undergoes a release operation, and a second flow type valve that allows the second flow line to be closed when the second series of at least one one filter sector of each disk undergoes a release operation;

the rotating filter includes a plurality of disks;

the chute is engaged within a tank, which includes a hopper that is located below the chute for collecting slurry resulting from the release;

the spray release device includes an upper chamber provided with at least one opening for supplying release fluid, and includes a series of punctures that are positioned above the disk or disks such that increasing pressure of the release fluid in the upper chamber causes release jets to be ejected to the main surfaces of the filter sectors.

The invention also provides a filtration method for separating a suspension into liquid/solids using a rotating filter including a trough containing the suspension, a device for spraying a fluid for release, and at least one disk that is non-rotatably connected to a main shaft, each the disk is partially immersed in the suspension and each disk includes a plurality of filter sectors, wherein each filter sector includes a structural element that is coated with a filter medium and a passage for connecting it to a flow line located along the main shaft, the method including the following steps:

a) filtering the suspension on each disk using a first or second series of at least one filter sector;

b) releasing, on each disk, a first or second series of at least one filter sector by spraying a release fluid, the method characterized in that it includes a nominal duty cycle during which a filtration operation on the first series of of at least one filter sector of each disk is performed simultaneously with a release operation on a second series of at least one filter sector of each disk, the main shaft being driven to a first angular position when the first series of at least one filter sector of each disk is impregnated with the suspension and when the second series of at least one filter sector of each disk is located above the suspension; and a filtering operation on a second series of at least one filter sector of each disk is performed simultaneously with a release operation on a first series of at least one filter sector of each disk, the main shaft being driven to a second angular position when the second series of at least one the filter sector of each disk is impregnated with the suspension and when the first series of at least one filter sector of each disk is located above the suspension.

In accordance with other advantageous features of the present method, the main shaft includes a first flow line that communicates with a first series of at least one filter sector of each disk, and a second flow line that is separate from the first flow line and communicates with a second series of at least one filter sector each disk, and during the release operation on the first series of at least one filter sector of each disk, the first flow path is blocked, and during the release operation on the second series of at least one filter sector of each disk, the second flow path is blocked;

each release operation is preceded by a sealing step during which close contact is established between each disc and the teeth of the comb, and each release operation is followed by a seal release step during which the tight contact is released;

the sealing step consists of bringing the retractable parts of the seal into an extended state in which they provide close contact, and the seal release step consists of bringing said retractable parts into a retracted state in which they provide the release of said tight contact;

the seals are advanced by pumping resulting from increased pressure in the fluid line that supplies at least two non-filter sectors on each disk, located between two series of at least one filter sector of each disk, through a supply channel located along the main shaft, and said seals are drawn in by pumping resulting from a pressure drop across said fluid line;

during the nominal cycle, the main shaft is alternately controlled to rotate 180° in a clockwise and then counterclockwise direction between the first angular position and the second angular position;

portions of sludge resulting from the release operations are partially injected back into the feed circuit of the device to irrigate the discs during the release operations.

One skilled in the art may also recognize additional benefits by examining the examples below, illustrated by the following accompanying graphics:

fig. 1 is a perspective view in longitudinal section corresponding to plane I-I in FIG. 2 showing a rotating filter in accordance with the present invention;

fig. 2 is a cross-sectional view according to plane II-II showing the rotating filter of FIG. 1;

fig. 3 is a longitudinal sectional view according to plane III-III, showing the extension of the seals, in this case the pumping of the diaphragms, with which the non-filtering sectors of the rotating filter in FIG. 1;

fig. 4 is a perspective cross-sectional view showing a portion of the rotating filter in FIG. 1;

fig. 5 is a perspective view showing the non-filtering sector of the rotary filter of FIG. 1, equipped with diaphragms;

fig. 6 is a cross-sectional view corresponding to plane IV-IV in FIG. 5, showing the non-filtering sector of the rotating filter when the diaphragms are evacuated;

fig. 7 is a cross-sectional view corresponding to plane IV-IV in FIG. 5, showing the non-filtering sector of the rotating filter when the diaphragms are inflated;

fig. 8 is a schematic view depicting the first stage of the filtration method in accordance with the present invention, when the main shaft of the rotating filter occupies the first angular position and during which filtration simultaneously begins on the first series of filter sectors of each disk, and torsion of the sediment occurs on the second series of filter sectors of each the disk and diaphragm on the non-filtering sectors are inflated;

fig. 9 is a schematic view showing the second stage of the filtration method according to the present invention, when the main shaft of the rotary filter is in the same angular position and during which filtration on the first series of filter sectors is simultaneously continued, a release operation is performed on the second series of filter sectors and the diaphragm on non-filtering sectors they are brought to an inflated state;

fig. 10 is a schematic view showing the third step of the filtering method in

- 3 043521 in accordance with the present invention, when the main shaft of the rotating filter remains in the same angular position and during which simultaneously filtration continues on the first series of filter sectors and the diaphragms on the non-filter sectors are pumped out;

fig. 11 is a schematic view showing the fourth step of the filtration method according to the present invention, during which the main shaft is rotated to the second angular position;

fig. 12 is a longitudinal sectional view according to the III-III plane showing compaction by inflating the diaphragms during the first step shown in FIG. 8;

fig. 13 is a longitudinal sectional view according to plane III-III showing the inflated state of the diaphragms during the second stage shown in FIG. 9;

fig. 14 is a longitudinal sectional view according to plane III-III showing seal removal by pumping out the diaphragms during the third step shown in FIG. 10;

fig. 15 is a longitudinal sectional view according to plane III-III showing the evacuated state of the diaphragms during the fourth stage shown in FIG. eleven.

In fig. 1 shows a rotating filter 10 intended to equip an industrial plant for separating a suspension into liquid/solids.

In the remainder of the description, by way of non-limiting example, the orientation will be used in accordance with the reference point V, L, T defining the vertical, longitudinal and transverse orientations shown in FIG. 1. In addition, identical or similar elements may be designated by the same reference numerals.

According to the embodiment shown in FIG. 1, the rotary filter 10 includes a trough 12 and a plurality of disks 14 that are non-rotatably connected to a main shaft 16. Here, the main shaft 16 is mounted so as to be rotatable about a longitudinal axis A1 which extends longitudinally through the tank 18, containing a chute 12 and discs 14.

As shown in particular in FIG. 2 and 3, the trough 12 is essentially in the shape of a half-cylinder, open at the top, having a diameter slightly larger than the diameter of the disks 14. The trough 12 is designed to supply slurry, in this case via a feed tube 20.

Here, the chute 12 is suspended in the center of the tank 18. In this embodiment, the tank 18 includes a main cylindrical wall 22 having a vertical axis A2, the main cylindrical wall 22 being continued at its lower axial end 24 by a hopper 26 and at its upper axial end 28 by a lid 30 bell shaped.

According to the illustrated embodiment, the rotary filter 10 is designed to operate under pressure, i.e. the chamber defined by the tank 18 is placed under pressure above atmospheric pressure to cause the filtrate to pass through the disks 14, then to the inside of the main shaft 16 and finally to the outlet channel of the main shaft 16, as will be shown in more detail below.

In this case, the spray device 32 is located in the cover 30 above the discs 14. In accordance with the illustrated embodiment, the spray device 32 includes a spherical cap 34, which in this case is soldered to the wall 36 in the shape of a truncated cone of the cover 30 so as to form at the top of the tank 18, an upper chamber 38 that is capable of containing a release fluid. The spherical cap 34 includes a series of punctures 40 that are positioned above the discs 14 such that increasing pressure of the release fluid in the upper chamber 38 causes release jets J1 to be ejected through the punctures 40 to the discs 14. The spray device 32 functions substantially like a shower head. .

The cover 30 is advantageously provided with an access hatch 42, which makes it possible to simplify cleaning and maintenance of the spray device 32. In this case, the access hatch 42 is provided with an opening 44 for supplying a release fluid.

According to another advantageous embodiment, the punctures 40 can be equipped with nozzles that are configured to form release jets J1 that are flat or have any other shape directed towards the main surfaces, i.e. radial surfaces, 14 disks.

In the rest of the description for disk elements or disk sectors, the main surface is understood to be the radial surface, i.e. a surface that extends in a transverse plane relative to the axis of the disk.

In accordance with the illustrated embodiment, flanges 46, in this case in the form of plates parallel to the disks 14, are fixed to the lower surface of the spherical cap 34 on both sides of the stack formed by all the disks 14 of the rotating filter 10, so as to form a spray zone above the disks 14.

It should be noted that the flanges 46 also serve to enhance the rigidity of the spherical cap 34 in a manner similar to reinforcing ribs.

The hopper 26 ends at its lower axial end with a sleeve 48 which allows the slurry resulting from the release operation to be removed.

- 4 043521

The release fluid, which may also be called a cleaning fluid, or a descaling fluid, or a rinsing fluid, is, for example, a mixture of water and sludge resulting from the release operation.

In this case, each disk 14 is formed by first and second series S1, S2 of filter sectors 50, and the second series S1, S2 are separated from each other by two non-filter zones 52, which are diametrically opposed.

In the illustrated embodiment, each series S1, S2 includes four filter sectors 50 and each non-filter zone 52 represents a non-filter sector 54.

It should be noted that the present invention is also applicable to the rotary filter 10, in which the series S1, S2 contains only one filter sector 50.

The first series S1 of filter sectors 50 is intended for communication with the first flow line 56 located in the main shaft 16, and the second series S2 of filter sectors 50 is intended for communication with the second flow line 58 located in the main shaft 16.

According to the embodiment shown in FIG. 4, each filter sector 50 includes a structural element 60 that is covered with a filter medium 62, such as a filter cloth, and at least one tube 64, in this case two, opening into one of the flow paths 56, 58 of the main shaft 16 through connecting holes 66, visible in Fig. 1.

The structural element 60 serves to support the filter medium 62. The filter medium 62 forms the interior of the filter sector 50 in which the filtrate flows.

Advantageously, as shown in FIG. 3-7, each non-filter sector 54 includes a solid body 68 in the form of a disk sector, which in this case is provided with through holes 70 and which includes a seal 74, 75 on each of the main surfaces 72, 73.

Here, each seal 74, 75 is an elastically deformable diaphragm 76, 77. Here, each diaphragm 76, 77 is attached to the solid body 68 at its peripheral edges 78 by mounting flanges 80. Thus, the peripheral edges 78 of each diaphragm 76 , 77 are clamped between the mounting flanges 80 and the solid body 68.

Each diaphragm 76, 77 includes a retractable portion 82 that consists of a movable main wall 84 and a wedge-shaped connecting portion 86 that connects the movable main wall 84 to the peripheral edges 78. As seen in FIG. 6, in this case the connecting part 86 has an S-shaped profile. Said connecting portion 86 is designed to be retractable as shown in FIG. 7, and thus allows the movable main wall 84 to be moved in a direction opposite to the solid main body 68.

Advantageously, each locking flange 80 includes, on the side of the movable main wall 84, a concave edge 88 that is designed to conform to the S-shape of the connecting portion 86.

Here, the diaphragms 76, 77 are generally made of an elastomer or rubber type material to take advantage of the connection portion 86 being flexible enough to be elastically deformed and thus easily return to its original shape after deformation.

The material of each diaphragm 76, 77 may advantageously include a core made of textile or other material that allows a certain degree of structural stress to be maintained in the diaphragm 76, 77.

These diaphragms 76, 77 do not allow the passage of the suspension. They do not perform a filtering function. They function as seals, as will be explained in more detail below.

An inlet tube 90 for pressurized fluid is located in the solid body 68. The inlet tube 90 communicates as shown in FIG. 2, with a supply passage 92 for a pressurized fluid, such as compressed air, located along the main shaft 16, in this case internally, to allow each diaphragm 76, 77 to be pumped by increasing pressure. Diaphragms 76, 77 thus form retractable seals.

The solid body 68 is, for example, formed from a steel sheet or even another material. In this case, it is attached to the main shaft 16 by means of a base 94, which is provided, in particular, with two pins 96 and a radial connecting tube 98, which communicates on one side with the supply channel 92 for the pressurized fluid and on the other side with the inlet tube 90 for compressed fluid.

The pins 96 ensure that the non-filter sector 54 is correctly positioned on the main shaft 16, preventing rotation of the non-filter sector 54.

Starting from the evacuated state of the diaphragms 76, 77 shown in FIG. 6, the supply of pressurized fluid through the inlet tube 90 results in an increase in pressure within the non-filter sector 54 in the cavity 100 defined by two diaphragms 76, 77 on either side of the solid body 68. The increase in pressure in the cavity 100 typically causes the movable bodies the walls 84 extend towards the outside of the non-filter sector 54 until the movable main walls 84 enter their inflated state, shown in FIG. 7.

- 5 043521

As can be seen in particular in FIG. 2, 3 and 4, the groove 12 includes ridge teeth 102, which are located above the slurry level on both sides of each disk 14. Here, each ridge tooth 102 is attached to a longitudinal edge 104 of the groove 12, for example, by screwing and extends to the main shaft 16 .

To ensure sufficient rigidity of the ridge teeth 102, each ridge tooth 102 includes a body that is substantially dovetail shaped, having a support leg 106 for securing it to the inner surface of the longitudinal edge 104 of the groove 12, and a rod 108 that extends from the upper end. support leg 106 to the free end 110 near the main shaft 16. In this case, each ridge tooth 102 includes a stiffener plate 112 that extends under the shaft 108 to the support leg 106.

Advantageously, a first series D1 of ridge teeth 102 is located on one side of the main shaft 16, and a second series D2 of ridge teeth 102 is located on the other side of the main shaft 16.

Thus, each disk 14 is clamped by four ridge teeth 102, two belonging to the first series D1 and two belonging to the second series D2.

Advantageously, the upper surface 114 of the shank 108 of each ridge tooth 102 is inclined downward from the main shaft 16, which, as will be seen, allows the slurry portions generated by the release operation to flow toward the outside of the trough 12.

As stated above, the main shaft 16 includes two internal flow paths 56, 58, or chambers, which are separated by a longitudinal dividing wall 116. The main shaft 16 is designed to be rotated by a drive device 118 between two extreme angular positions P1, P2: a first angular position P1, which is shown in Fig. 1-3 and in which the first series S1 of filter sectors 50 is impregnated with the suspension, and a second angular position P2, which is diametrically opposite to the first angular position P1 and in which the second series S2 of filter sectors 50 is impregnated with the suspension.

In the first angular position P1, all filter sectors 50 of the first series S1 are placed in the trough 12 under the ridge teeth 102, while all filter sectors 50 of the second series S2 are placed above the trough 12 above the ridge teeth 102. Non-filter sectors 54, which separate the S1 series from the S2 series of filter sectors 50 of each disk 14, are placed at the height of the ridge teeth 102 in such a way that the pumping of the diaphragms 76, 77 provides close contact between the diaphragms 76, 77 and the side walls 120, 121 of adjacent teeth 102 ridges in the area of the rods 108.

Advantageously, all the disks 14, of which in this case there are eight, are located in the same way as the trough 12 relative to the main shaft 16. Thus, in the first angular position P1, the first series S1 of the filter sectors 50 of all disks 14 is impregnated with the suspension, while the second the S2 series of their filter sectors 50 is located above the D1, D2 series of comb teeth 102.

The second angular position P2 is symmetrical to the first angular position P1 relative to the longitudinal axis A1.

Advantageously, the main shaft 16 is equipped with a first flow-type valve 122, in this case located at its downstream end, which makes it possible to shut off the first flow line 56 of the filtrate extraction side, and a second flow-type valve 124, in this case located at its downstream end. , which makes it possible to block the second flow line 58 of the filtrate extraction side.

The operation of the rotary filter 10 will now be described, particularly with reference to FIG. 8-15, which illustrate the various steps of this filtration method. It should be noted that in FIG. 12-15 show the shape of the diaphragm 76, 77, respectively, during the steps shown in FIG. 8-11.

The rotating filter 10 is continuously fed with slurry so as to keep the trough 12 full.

In fig. 8 shows the rotating filter 10 after it has already gone through many operating cycles, so that the second series S2 of filter sectors 50 located above the series D1, D2 of ridge teeth 102 is already covered with sediment. In addition, the hopper 26 is already filled with sludge resulting from the previous release steps.

In fig. 8 shows the first stage of the filtration process, during which the suspension is filtered by a first series S1 of filter sectors 50, which are lowered into the suspension. Thus, under the influence of the pressure prevailing in the tank 18, the filtrate passes through the filter medium 62 of the filter sectors 50. The filtrate passes into the first flow line 56 of the main shaft 16, passing through the connecting holes 66, and is pumped out of the main shaft 16, passing through the first valve 122 in-line type, which is driven to the open position.

Simultaneously, during said first step, the second flow-type valve 124 is driven to the open position. This provides a positive difference between the pressure in the tank 18 and the pressure in the second flow line 58 of the main shaft 16, which makes it possible to perform the operation of torsion of the sediment on the filter sectors 50 of the second series S2.

Simultaneously, during said first stage, pressure is applied to the diaphragms 76, 77, as shown in FIG. 12 to inflate them to establish tight contact between the comb teeth 102

- 6 043521 and non-filtering sectors 54.

In fig. 9 shows the second stage of the method, during which the suspension continues to be filtered by the first series S1 of filter sectors 50, since the main shaft 16 still occupies its first angular position P1 and since the first flow-type valve 122 is still open.

Simultaneously, during said second step, the second flow-type valve 124 is driven to the closed position. This creates an equilibrium between the pressure in the tank 18 and the pressure in the second flow line 58 of the main shaft 16, which makes it possible to perform an effective release operation on the filter sectors 50 of the second series S2 using the spray device 32, which directs the release jets J1 to the filter sectors 50 and more specifically on the main surfaces of the filter sectors 50 of the second series S2. Diaphragms 76, 77 are kept inflated on their non-filtering sectors 54.

As shown in FIG. 9, as a result of the release operation, sludge is formed, i.e. a mixture of release fluid and solids coming from the sludge. Said slurry flows down along the ridge teeth 102 to the hopper 26.

As shown in FIG. 13, the seal achieved before pumping the diaphragms 76, 77 prevents sludge from entering the trough 12 by passing between the discs 14 and the ridge teeth 102. This therefore makes it possible to provide excellent filtration efficiency at both the first series S1 of filter sectors 50 in the trough 12 and the release at the second series S2 of filter sectors 50.

In fig. 10 shows the third stage of the process, during which the suspension continues to be filtered by the first series S1 of filter sectors 50, since the main shaft 16 still occupies its first angular position P1 and since the first flow-type valve 122 is still open.

Simultaneously, in said third step, the atomizing device 32 is switched off since the release operation is completed and the diaphragms 76, 77 are evacuated, as shown in FIG. 14. The main shaft 16 is still in its first angular position P1, and the second flow type valve 124 is still closed.

Evacuation of the diaphragms 76, 77 prevents the diaphragms 76, 77 from rubbing against adjacent ridge teeth 102 as the main shaft 16 rotates, which could cause premature wear.

In fig. 11 shows the fourth step of the method, during which the main shaft 16 rotates, in this case in a counterclockwise direction, from its first angular position P1 to its second angular position P2. In fig. 11, the main shaft 16 is shown at an intermediate angular position Pi between the first angular position P1 and the second angular position P2.

During said fourth step, the first flow-type valve 122 is held in an open position, allowing filtration to continue in the filter sectors 50 of the first series S1, provided they are saturated with the slurry. As can be seen in FIG. 11, the filter sectors 50 of the first series S1 that leave the suspension begin their spinning phase, while those that are still saturated with the suspension continue filtration.

During said fourth step, the second flow-type valve 124 is held in a closed position such that the filter sectors 50 of the second series S2, gradually entering the trough 12, do not begin filtration.

During the fourth stage, the diaphragms 76, 77 remain evacuated, as shown in FIG. 15.

At the end of the fourth stage, after turning 180° counterclockwise relative to the first angular position P1, the main shaft 16 takes its second angular position P2, and the filter sectors 50 of the first series S1 are in the upper position above the series D1, D2 of the ridge teeth 102, in while the filter sectors 50 of the second series S2 are impregnated with the suspension.

Thus, as shown in FIG. 8 and 12, after the fourth stage, the first stage begins again, but including filtration through a second series S2 of filter sectors 50 in the lower part and including torsion through a first series S1 of filter sectors 50 in the upper part.

The complete nominal operating cycle thus includes the above four steps repeated twice so that the S1 series and S2 series of the filter sectors 50 proceed to filtration and release.

Preferably, at the end of the nominal operating cycle, the main shaft 16 is rotated in the opposite direction, in this case in a clockwise direction, to return to its first angular position P1 from the second angular position P2.

Rotation in a clockwise and counterclockwise direction in an alternating manner, in particular, makes it possible to avoid twisting of the control cables of the flow type valves 122, 124, which are located on the main shaft 16. This also facilitates the positioning of the means for supplying pressurized fluid to the channels 92 feeds of the main shaft 16.

Advantageously, a portion of the slurry portions generated during the release steps are recovered at the outlet of the hopper 26, then partially injected back into the feed circuit of the spray device 32. Thus, a portion of the release fluid is formed. Its recycling makes it possible

- 7 043521 reduce the consumption of other release fluids and minimize the volume of sludge batches generated, regardless of the time of sludge formation.

The rotary filter 10 and the filtration method in accordance with the present invention are particularly suitable for industrial installations in which it is desirable to minimize the time of sediment formation, for example, where it is desired to have a sediment formation time of less than 2 minutes.

For example, the filtering method of the present invention may be implemented limiting the first stage to 15 seconds, the second stage to 90 seconds, the third stage to 5 seconds, and the fourth stage to 10 seconds.

The advantage of the rotating filter 10 in accordance with the present invention is that it facilitates maintenance operations. For example, removal of the cover 30 allows access to the interior of the tank 18 and relatively easy removal of the main shaft 16 or discs 14 to replace the filter media 62. Likewise, an access hatch 42 located in the cover 30 allows easy access to the spray device 32 for cleaning it and to unblock punctures 40 that may become clogged due to sludge recirculation.

According to an option, the above-described spray device 32 can be replaced by an inclined device equipped with a plurality of spray nozzles distributed above the disks 14.

Of course, the present invention also relates to a rotating filter 10 operating under vacuum conditions, where the liquid phase of the suspension is sucked through the filter sectors 50 and through the flow lines 56, 58 of the main shaft 16.

In an embodiment (not shown), the ridge teeth 102 may be mounted on the groove 12 to allow movement between active positions, as shown in FIG. 2-4, where they are in close contact with the non-filter sectors 54, and a retracted position in which they are no longer in contact with the non-filter sectors 54. In this case, the diaphragms 76, 77 can be omitted and the ridge teeth 102 are driven into a retracted position. position during the third and fourth stages to ensure the rotation of the discs 14.

List of reference positions.

- Rotating filter;

- gutter;

- disks;

- main shaft;

- tank;

- feeding tube;

- main cylindrical wall;

- lower axial end;

- bunker;

- upper axial end;

- lid;

- spraying device;

- spherical cap;

- wall in the shape of a truncated cone;

- upper chamber;

- punctures;

- access hatch;

- feed hole;

- flanges;

- bushing;

- filter sectors;

- non-filtering zones;

- non-filtering sectors;

- first flow pipeline;

- second flow pipeline;

- structural elements;

- filter medium;

- passages;

- connecting holes;

- solid main parts;

- through holes;

, 73 - main surfaces;

, 75 - seals;

, 77 - diaphragm;

- peripheral edges;

- mounting flanges;

-

Claims (21)

82 - retractable parts; 84 - movable main walls; 86 - connecting parts; 88 - concave edges; 90 - inlet pipes; 92 - channels; 94 - bases; 96 - pins; 98 - connecting tubes; 100 - cavities; 102 - comb teeth; 104 - longitudinal edges; 106 - support legs; 108 - rods; 110 - free ends; 112 - stiffening plates; 114 - upper surfaces; 116 - dividing wall; 118 - drive device; 120, 121 - side walls; 122 - first flow-type valve; 124 - second flow-type valve; A1 - longitudinal axis; A2 - vertical axis; D1 - first series of comb teeth; D2 - second series of comb teeth; J1 - release jets; S1 - the first series of filter sectors; S2 - the second series of filter sectors. CLAIM 1. A rotating filter (10) for separating a suspension into liquid/solids, comprising a trough (12) containing the suspension, a device (32) for spraying fluid for release and at least one disk (14) which is connected without rotatable with the main shaft (16), each disc (14) being partially immersed in the slurry and each disc (14) including a plurality of filter sectors (50), each filter sector (50) including a structural element (60) that is covered filter medium (62), and a passage (64) for connecting said filter sector (50) with a flow line (56, 58) located along the main shaft (16), characterized in that each disk (14) includes a first series (S1) from at least one filter sector (50), which is separated from the second series (S2) of at least one filter sector (50) by two non-filter zones (54); the main shaft (16) includes a first flow line (56), which communicates with the first series (S1) of at least one filter sector (50) of each disk (14), and a second flow line (58), which communicates with the second series ( S2) from at least one filter sector (50) of each disk (14); said rotating filter (10) includes teeth (102) of ridges that are located above the slurry level on each side of each disk (14), the main shaft (16) being configured to be in at least a first angular position (P1), in in which the first series (S1) of at least one filter sector (50) of each disk (14) is placed under the teeth (102) of the combs, impregnated with the suspension to be filtered, and in which the second series (S2) of at least one filter sector (50) of each disk (14) is placed over the comb teeth (102), with each non-filter zone (52) adjacent to one ridge tooth (102) on each of its surfaces; a second angular position (P2), in which a second series (S2) of at least one filter sector (50) of each disk (14) is placed under the teeth (102) of the combs, impregnated with the suspension to be filtered, and in which the first series (S1 ) of at least one filter sector (50) of each disc (14) is placed over the comb teeth (102), with each non-filter zone (52) adjacent to one ridge tooth (102) on each of its surfaces to provide release on a series (S1, S2) from at least one filter sector (50) of each disk (14) placed above the teeth (102) of the combs, while filtration of the suspension continues on another series (S1, S2) of at least one filter sector (50) of each disk (14), placed under the teeth (102) of the combs. 2. The rotary filter (10) according to the preceding paragraph, characterized in that it includes at least one seal (74, 75) which is located between each non-filter zone (52) and the adjacent ridge tooth (102), when the main shaft (16 ) occupies the first angular position (P1) and when the main shaft (16) occupies the second angular position (P2). 3. The rotary filter (10) according to the preceding claim, characterized in that each seal (74, 75) includes a retractable portion (82) which is switchable between an extended state in which it creates intimate contact between the non-filtering zone (52) and the adjacent comb tooth (102), and a retracted state in which there is no longer intimate contact between the non-filtering zone (52) and the adjacent ridge tooth (102). 4. Rotating filter (10) according to the previous paragraph, characterized in that each seal (74, 75) includes at least one elastically deformable part. 5. Rotating filter (10) according to claim 3 or 4, characterized in that each seal (74, 75) is located on a non-filtering zone (52). 6. Rotating filter (10) according to the previous paragraph, characterized in that each non-filtering zone (52) includes a disk sector, called a non-filtering sector (54), which is located between the filtering sector (50) of the first series (S1) and the filtering sector (50 ) second series (S2). 7. Rotary filter (10) according to the preceding paragraph, characterized in that each non-filter sector (54) includes at least one inlet tube (90) for fluid under pressure, which is connected to a supply channel (92), which is located along the main shaft (16) so as to allow each seal (74, 75) to be extended by pumping and each seal (74, 75) to be retracted by pumping. 8. Rotating filter (10) according to any one of claims 6 or 7, characterized in that each seal (74, 75) is a diaphragm (76, 77), which is attached to the non-filtering sector (54) by its peripheral edges (78) and which includes a movable main wall (84) which is connected to the peripheral edges (78) by means of a wedge-shaped connecting part (86). 9. Rotating filter (10) according to any of the previous claims, characterized in that the teeth (102) of the combs are attached to the edges of the trough (12). 10. Rotating filter (10) according to any one of the preceding claims, characterized in that each tooth (102) of the comb is inclined downward from the main shaft (16) to the outer side to facilitate the flow of portions of sludge formed by the mixture to the outer side of the trough (12) a fluid used in the release of filter cakes removed from the filter sectors (50). 11. Rotary filter (10) according to any of the preceding paragraphs, characterized in that the main shaft (16) is equipped with a first flow-type valve (122), which makes it possible to close the first flow line (56) when the first series (S1) of at least at least one filter sector (50) of each disk (14) is subjected to a release operation, and a second flow-type valve (124), which makes it possible to close the second flow line (58) when the second series (S2) of at least one filter sector (50 ) of each disk (14) undergoes a release operation. 12. Rotating filter (10) according to any of the previous claims, characterized in that it includes a plurality of disks (14). 13. Rotary filter (10) according to any one of the preceding claims, characterized in that the trough (12) is engaged inside a tank (18), which includes a hopper (26), which is located under the trough (12) for removing portions of sludge generated as a result of release. 14. Rotary filter (10) according to any one of the preceding claims, characterized in that the spray release device (32) includes an upper chamber (38) provided with at least one opening (44) for supplying a release fluid, and includes a series punctures (40) which are placed above the disk or disks (14) such that the increase in pressure of the release fluid in the upper chamber (38) results in the ejection of release jets (J1) towards the main surfaces of the filter sectors (50). 15. A filtration method for separating a suspension into liquid/solids using a rotating filter (10) including a trough (12) containing the suspension, a device for spraying a fluid for release and at least one disk (14) which is connected without possibility rotation with the main shaft (16), each disk (14) is partially immersed in the suspension and each disk (14) includes a plurality of filter sectors (50), with each filter sector (50) including a structural element (60) that is covered with filter media medium (62), and a passage (64) for connecting it with a flow line (56, 58) located along the main shaft (16), the method including the following operations: a) filtering the suspension on each disk (14) using a first or second series (S1, S2) of at least one filter sector (50); - 10 043521 b) releasing on each disk (14) on the first or second series (S1, S2) from at least one filter sector (50) by spraying a release fluid, the method characterized in that it includes a nominal duty cycle, in time during which the filtering operation on the first series (S1) of at least one filter sector (50) of each disk (14) is performed simultaneously with the release operation on the second series (S2) of at least one filter sector (50) of each disk (14 ), wherein the main shaft (16) is brought to the first angular position (P1) when the first series (S1) of at least one filter sector (50) of each disk (14) is impregnated with the suspension and when the second series (S2) of at least at least one filter sector (50) of each disk (14) is located above the suspension; and a filtering operation on a second series (S2) of at least one filter sector (50) of each disk (14) is performed simultaneously with a release operation on a first series (S1) of at least one filter sector (50) of each disk (14) , wherein the main shaft (16) is brought to a second angular position (P2) when the second series (S2) of at least one filter sector (50) of each disk (14) is impregnated with the suspension and when the first series (S1) of at least one filter sector (50) of each disk (14) is located above the suspension. 16. The filtration method according to the previous paragraph, characterized in that the main shaft (16) includes a first flow line (56), which communicates with the first series (S1) of at least one filter sector (50) of each disk (14), and a second a flow line (58) that is separated from the first flow line (56) and communicates with a second series (S2) of at least one filter sector (50) of each disk (14), and that during the release operation on the first series (S1 ) from at least one filter sector (50) of each disk (14) the first flow line (56) is closed and during the release operation on the second series (S2) from at least one filter sector (50) of each disk (14) the second flow line (58) blocked. 17. The filtration method according to any one of claims 15 or 16, characterized in that each release operation is preceded by a compaction step, during which close contact is established between each disk (14) and the teeth (102) of the comb, and each release operation is followed by a step removal of the seal, during which the tight contact is removed. 18. The filtration method according to the preceding claim, characterized in that the sealing step consists of bringing the retractable parts (82) of the seals (74, 75) into an extended state where they provide tight contact, and the seal removal step consists of bringing said retractable parts (82 ) into a retracted state in which they ensure the removal of said tight contact. 19. The filtration method according to the preceding claim, characterized in that the seals (74, 75) are advanced by pumping resulting from increased pressure in the fluid line that supplies at least two non-filter sectors (54) on each disk (14 ), placed between two series (S1, S2) of at least one filter sector (50) of each disk (14), through a feed channel (92) located along the main shaft (16), and the mentioned seals (74, 75) are drawn in by pumping resulting from the pressure drop across said fluid line. 20. The filtration method according to any one of claims 15 to 19, characterized in that, during a nominal cycle, the main shaft (16) is alternately controlled to rotate 180° in a clockwise direction and then counterclockwise between the first angular position (P1) and the second angular position (P2). 21. Filtration method according to any one of claims 15 to 20, characterized in that portions of sludge resulting from the release operations are partially injected back into the feed circuit of the device (32) for irrigating the discs (14) during the release operations. -