FR2459069A1 - FILTERING INSTALLATION, AND METHOD OF OPERATING THE INSTALLATION - Google Patents

Abstract

THE INSTALLATION INCLUDES AN ENDLESS FILTERING BAND 10 THAT CAN BE DISCONTINUALLY MOVED THROUGH SEVERAL PROCESSING STATIONS WHERE IT IS IMMOBILIZED FOR A CERTAIN USEFUL DURATION OF THE OPERATING CYCLE. FEEDING DEVICES 40, 46, 52, 58, LOCATED ABOVE THE FILTER TAPE 10, DELIVER THE MIXTURE TO BE FILTERED THEREFORE, AND ALSO DISTRIBUTE VARIOUS PROCESSING AGENTS. BELOW THE UPPER STRAND OF THE FILTERING BAND ARE PROVIDED SUCTION BOXES 12A TO 12E, THE SUCTION PROVIDED BY THESE BOXES CONNECTED TO A PUMP 20 IS INTERRUPTED DURING THE ADVANCING TIME OF BAND 10. THANKS TO A PROGRAMMER , THE START AND OR THE END OF THE SUPPLY BY THE FEEDING DEVICES 40, 46, 52, 58, AS WELL AS THE START AND OR THE END OF THE SUCTION, CAN BE FREELY CHOSEN, WITHIN THE TOTAL USEFUL LIFE OF THE CYCLE.

Description

The present invention relates to an installation of

  filtering, including a movable filter band,

  at least one processing station, and immobilized for a certain total operating life of the operating cycle, and at least one feed device for feeding an agent over the filter band and at least one suction device located below the band

  filter, the suction being interrupted during the

progress made.-

  A filter installation of this type is known

  by the German patent application DE-OS 23 49 215.

  In such a filtering installation, the device

  feedstock supplying a slurry of solid material in a liquid and filtering, as well as the feeder distributing a particular liquid agent which is used to treat the deposition of solid material

  on the filter belt, operate permanently

  you. This mode of operation makes it possible to classify the

  filtration filter known here recalled in the category

  general condition of the installations operating continuously.

  In addition, there are filtration facilities

  endiscontinuous operation, in which one puts into operation and out of service, at successive times which

  may be freely chosen, various

  as well as suction devices,

  so that at a given moment, throughout the installation,

  filtering, only one

  tion. In contrast to the conditions

  In this case, continuous operation of the solid suspension in a liquid, the treatment liquid and the filtrate is not achieved. However these facilities operating in discontinuous have the advantage to allow the free choice

treatment times.

  The object of the invention is to provide an installation

  improved filtering, which combines the advantages of continuous and discontinuous

the inconvenients.

  For this purpose, it is essentially proposed, according to the present invention, that the beginning and / or end of the a-led by the aforementioned feeding device and / or

  aspiration can be freely chosen, within

  the total service life of the operating cycle

installation.

  For the practical realization of this, the beginning and / or end of the feed or suction can be

  controlled by at least one programmer, whose sequencing

  this is triggered by the start of the total operating life of the cycle. If, within this total cycle life, it is desired to define several partial useful times, separated from each other by switching times, at least one can be provided.

  two programmers, the triggering of the second

  setting is ordered at the end of the first programmer sequence. Each programmer can, of course,

  simultaneously control several switching processes

  tion, for example by controlling both the valves of the supply device (s), and the valves

the suction device or devices.

  The conformation of the filter installation

  object of the invention allows various methods of

  interesting features of this installation, which are also

  part of the present invention:

  According to a first embodiment of a project

  the original operating license applicable to such

  filtering installation, comprising a feeding device

  for supplying a mixture of liquid and solid phase, and following this feeding device, in the direction of advancement of the filtering band, at least one feed device for dispensing a solid material treatment agent deposited

  on the filter belt, the feed of the mixture in free phase

  Both the solid and / or the treatment agent are interrupted before the end of the total operating life of the operating cycle, while the suction continues until the end of the total operating life of the operating cycle. This procedure may be characterized by the expression "dry progress", taking into account the following observation: because of

  bringing the suspension of solid material into a

  the fluid and / or the distribution of the treatment liquid are interrupted before the end of the total useful life of the cycle and while the suction continues, it is ensured that at the time of the new start of the progress of the filter band, there will not remain on the strip any liquid that might, during

  the acceleration or slowing down of the band,

  to kill an uncontrolled movement and to reach areas of the filter strip where it would be undesirable.It is also ensured that no quantity of liquid will pass, driven by the filtering band, in the region of another feeding device dispensing a treatment liquid, o would form a mixture of these two liquids, a mixture that could affect the effectiveness of treatment and prevent the separation of filtrates

according to the desired way.

  In a second mode of implementation of a pro-

  an original operating license for an installation

  filtering according to the invention, comprising a feed device for feeding a mixture of liquid and solid phase, and following this feed device, in the direction of advance of the filter belt, at least one feeding device for the

  distribution of a solid matter treating agent

  deposited on the filter strip, the suction is de-

  delayed, compared to the beginning of

  the total useful life of the operating cycle. This model

  of operation guarantees - insofar as the supply of

  the suspension is interrupted before the start of the

  ration that the suspension can be divided

  more evenly on the filter strip, before the suction starts. The distribution of the treatment agent is advantageously interrupted, too, before the start of aspiration, which allows a longer action of the treatment agent on the materials.

  solids deposited on the filter band, so a better

  their use of a given total volume of treatment agent. The conformation of the filtering apparatus which is the subject of the invention also offers the possibility of successively involving several agents of

  treatment, distinct from each other.

  According to yet another embodiment of the method according to the invention, a treatment agent is firstly distributed, the aspiration is triggered after

  interruption of the distribution of this agent

  and, with some delay relative to the start of aspiration, but also during this aspiration, at least one treatment agent (the same or another) is again distributed; in this way, it is obtained that the treatment agent, - corresponding to a first treatment, which has combined with foreign bodies during the treatment period, will be replaced by a new quantity of pure treatment agent, just

  before the next advance of the filter belt.

  In any case, the invention will be better understood

  with the following description, with reference to the

  annexed schematic drawing representing, as an example

  non-limiting ple, an embodiment of this filtering installation, and illustrating some embodiments of the operating method of said installation: Figure 1 is a very schematic representation of a filter installation according to the invention; Figure 2 is a diagram showing various cycles

  typical operations, according to the invention, in comparison

  reason with a known procedure.

  In FIG. 1 is indicated, at 10, a band without

  filtering end. The upper strand of this filter band

  it passes over a succession of suction boxes 12a, 12b, 12c, 12d, 12e arranged in line in the direction of advance of the strip 10. Each of these suction boxes 12a to 12e is connected by

  via a suction duct, respectively

  14a to 14d, to a separator, respectively 16a to

  16d. All the separators 16a to 16d are connected to a con-

  common vacuum duct 18, connected to a pump

  20. From each separator 16a to 16d par-

  filtrate conduits 22a to 22d. On the suction lines 14a to 14d are interposed stop valves, respectively 24a to 24d, which allow

  to interrupt the sucking effect exerted on the different

  Suction boxes 12a to 12e. Other valves 26a to 26d are used to vent the ducts 14a to 14d and, therefore, the suction boxes 12a to 12e.

  The filterless endless belt 10 is movable,

  This discontinuous advance is controlled, each time, by the displacement of a return roller 30, from the position indicated in solid lines towards the position indicated to the right in line. end, while the lower strand of the filter band 10 is stopped by means of a brake 32. During this advance movement, the suction boxes 12a to 12e are placed in the open air, so that they do not exert any braking effect on the upper run of the filter band 10. To compensate for the displacement of the return roller 30, there is provided another movable return roller 34, arranged between two

  fixed return rollers 36 and 38; while the rou-

  the return water 30 moves from left to right, the return roller 34 moves from the position indicated in solid lines to the position to the left and 6 l indicated in fine lines. When this movement is over,

  the suction boxes 12a to 12e are reset to

  the brake 32 is released, and the return roller 34 is returned from left to right by means of a pneumatic cylinder, which simultaneously returns the return roller 30 to its initial position by a return movement. from right to left. The return roller 30 is

  also associated with a pneumatic cylinder.

  Above the upper strand of the endless band

  filter 10 is mounted a first feed device

  40, for feeding a suspension of solid material into a liquid; this feeder 40 comprises a valve 42 and distribution means 44. In the direction of advance of the filtering belt 10 come

  then: a feeding device 46 for a first

  first treatment agent, with a stop valve 48 and distribution means 50, then a supply device 52 for another treatment agent, with its stop valve 54 and its distribution means 56, and finally a device 58 power supply with its

  stop valve 60 and a dispensing nozzle 62.

  On the lower end of the filtering endless belt

  10 is a washing tub 64, with a supply duct 66 and a starting duct 68 for a washing liquid, a shut-off valve 70 and a watering nozzle 72.

  Shutoff valves 24a. at 24d, the intermediate valves

  in the open air 26a to 26d, and the feed valves

  42,48, 54 and -60 are controlled by means of a programmer. This programmer can be coupled with a timer which controls the running and stopping times of the filtering band 10, for example

  in such a way that the programmer receives a pre-

  first starting impulse delivered by the order

  progress, at the beginning of the banana movement.

  - 10, while the sequence comprising the subsequent instants of maneuvering the different valves is fixed by means of one or more timers; the total running time of these timers, which occur one after the other, corresponds to the cycle of the advancing mechanism (ie the sum of the stopping time and the running time). FIG. 2 shows, at A, a typical known procedure in which a slurry of solid material in a liquid is fed continuously, i.e. during

  the entire duration T of the cycle, by the feeding device

  40 (top line of the diagram). The device

  feed 46 also permanently distributes a

  treatment (which is also symbolized by

  the upper line). The aspiration is interrupted only

  during the forwarding period t0, so that the filter belt can be moved easily, the suction device remains in operation for the entire time.

useful life t of the cycle.

  According to a first mode of implementation of the

  according to the invention, illustrated in part B of the di-

  gram, the feeding device 40 bringing the sus-

  pension is in service during the period of advancement tO

  and for part of the total useful life t (that is,

  that is, during the partial useful times t1 and t2).

  The feed device 46, and possibly the following feeding devices 52 and 58 for the distribution of the treatment liquids, remain

  simultaneously in service (see the top line).

  The aspiration remains in operation, as symbolized by the lower line, throughout the useful life t of the cycle. It is recognized that after the end of the partial useful life t2, it is still possible, during the partial duration t3, to suck up a certain quantity

  liquid that has collected on the filter strip

te 10.

  In another embodiment of the method which is the subject of the invention, illustrated by part C of the diagram, the supply of the suspension by the device

  40 and the distribution of treatment liquid

  The supply device 46, as well as possibly the subsequent supply devices 52 and 58, take place only during the forward period t0 (upper line). However, we can

  also consider, alternatively, that the supply of the suspension

  during the entire cycle, and that only the supply of the treatment liquid (s) is

  limited to the duration of progress tO (upper line).

  The important point here is that the suction only starts after the partial working time t1, so that the amount of treatment liquid distributed on the filter belt during the running time t0

is used optimally.

  According to yet another embodiment of the process according to the invention, illustrated in part D of the diagram, the suspension and the treatment liquid are fed only during the period of advance t0 (the suspension may however, alternatively, to be brought

  throughout the duration T of the cycle). The aspiration is

  for the duration of the cycle.

  during the partial useful life t2, and as the symboli-

  If the hatching is reversed, another treatment liquid is dispensed. Concretely, this can be achieved by providing that the valve 60 is a valve

  multi-lane allowing the successive feeding of di-

  to treatment liquids. The separation of the filtrate from the suction side can also be effected in this case by means of multi-way valves placed in the region of the valve 24d. Finally, in a variant of the method which is the subject of the invention illustrated in part E of the diagram, a treatment liquid is firstly dispensed during the advancement of the endless filtering band, the suction subsequently starts at $ 5 and only after the partial useful life tl, and more

  late in the cycle, after the part-time

  the t2, is distributed another liquid treatment of the

same kind.

  With regard to the realization of the feeding devices, it is still to be noted that the device

  58 is adapted for distributing liquid treatment

  During the service life t of the cycle and during the running time t0 of the band, thanks to its nozzle i allowing a distribution of the liquid over a large area. The feeding means 40, 46 and 52 may also be shaped to provide a distribution over an extended area, but they may also be made in such a way that they discharge the liquid only along a line transverse to the

  direction of advancement (arrow 28), in which case they may

  or during the entire service life of the cycle by describing an alternating movement as illustrated by the arrow 76, in the

direction of advancement.

  The methods of implementation of the method indicated A to E can still be combined, certain devices

  feeding apparatus operating in accordance with one of the

  and other devices operating in accordance with

other scheme.

  The control device can finally be freely programmed, which means, on the one hand, that the durations

  partial usefulness tl, t2, t3 of the cycle can be

  vary in relation to each other

  on the other hand, that the different work programs, such as those A to E, may be

  choice, to the various feeding and vacuum devices

ration.

Claims (9)

-BEVENDICATIONS -   1.- Filtering installation, comprising a   filtering band (10) movable for a period of time   cement (tO), through at least one treatment station, and immobilized for a certain total useful life (t) of the operating cycle, as well as at least one feed device (40,46,52,58) for bringing an agent over the filter belt and at least   a suction device (12a, 12b, ... 12e) located   under the filter belt, the aspiration being   interrupted during the period of advancement (tO), which is   in that the beginning and / or end of the feeding by the aforesaid feeder (40,46,52,58) and / or   suction can be freely chosen   the total useful life (t) of the cycle of operation of the installation.   2.- Filtering installation according to the claim   1, characterized in that the beginning and / or end of the supply or the suction are controlled by at least one programmer, whose sequence is triggered by the beginning of the total useful life (t) of the cycle. operation.   3.- Filtering installation according to the claim   2, characterized in that at least two programs   are planned, the triggering of the second program-   being controlled at the end of the first programmer sequence. 4.Process of operating a plant   filtering according to any one of claims 1 to 3,   comprising a feed device (40) for feeding a mixture of liquid and solid phase, and following this feed device (40), in the direction of advancement of the filter band (10) , at least   a feeding device (46, 52, 58) for the distribution   of a solid-state treatment agent de-   placed on the filtering band (10), characterized in that the supply of the mixture in the liquid and solid phase and / or of the treatment agent is interrupted before the end of the total useful life (t) of the operating cycle, while the aspiration continues until the end of   the total useful life (t) of the operating cycle.   5.- Method for operating a wire installation   trage according to any one of claims 1 to 3,   comprising a feeding device (40) for the soul   from a mixture of liquid and solid phase, and following   of the feed device (40), in the direction of travel of the filter belt (10), at least one   feeding device (46,52,58) for the distribution   treatment of the solid substance   on the filter band (10), possibly in combination with   pairing with the method according to claim 4, characterized in that the suction is initiated with a certain delay, relative to the beginning of the useful life   total (t) of the operating cycle.   6. A process according to claim 5, characterized in that   that the distribution of the treatment agent is   broken before the start of aspiration.   7.- Method for operating a wire installation   trage according to any one of claims 1 to 3,   comprising a feeding device (40) for the soul   a mixture of liquid and solid phase, and following this feeding device (40), in the direction of advancement of the filtering band (10), at least one   feeding device (46,52,58) for the distribution   treatment of the solid material deposited on the filter belt (10), optionally in combination with the method according to any of the   Claims 4 to 6, characterized in that several   treatment agents, distinct from one another, intervene successively.   8.- Operating method of a plant   filtering according to any one of claims 1 to   3, comprising a feeding device (40) for feeding a mixture of liquid and solid phase and following this feed device (40), in the direction of advance of the filtering band (10). ), at least   a feeding device (46, 52, 58) for the dis-   an agent for treating the solid material deposited on the filter web (10), optionally in combination with the process according to any one of   Claims 4 to 7, characterized in that an agent of   treatment is first distributed, in that the aspira-   tion is triggered after interruption of the   treatment agent, and in that, with a delay in relation to the start of aspiration, but also during this aspiration, at least one agent of   treatment (the same or another) is distributed again.   9.- Filtering installation according to any one   Claims 1 to 3, characterized in that at least   a feeding device (40,46,52,56) and / or at least one suction device (12a, 12b, ..., 12e)   can be monitored during operation, followed by   different work programs.