FR2558078A1 - APPARATUS FOR CHEMICALLY REMOVING SOLID MATERIAL FROM WORKPIECES DURING CHEMICAL TREATMENT IN A LIQUID - Google Patents

Abstract

THE INVENTION RELATED TO AN APPARATUS FOR CHEMICALLY REMOVING SOLID MATERIAL FROM PARTS UNDER CHEMICAL TREATMENT IN A LIQUID. THE APPARATUS 10 INCLUDES A TREATMENT CHAMBER IN WHICH PARTS HAVE BEEN SUBJECT TO TREATMENT WITH A CHEMICAL SOLUTION BY GOING OVER FILTERS 36, 37 WHICH ALLOW THE CHEMICAL SOLUTION DROPPING PARTS A, BUT RETAIN SOLIDS REMOVED BY THIS SOLUTION. THE DEVICES 41, 42 FOR WASHING THE FILTERS 36, 37 PERIODICALLY REMOVE THE SOLID MATERIAL ACCUMULATED BY MAKING IT PASS THROUGH A DRAIN 40 FOR EVACUATION. APPLICATIONS: MANUFACTURE OF PRINTED CIRCUIT BOARDS AND BOARDS, ETC.

Description

The invention applies to the electrical industry

  tronic, and more particularly to industrial processes that have emerged for the manufacture of printed circuit boards, printed circuit boards and for the treatment of like parts. In this industry and in related fields such as the industrial production of electrolytic deposits, it has become commonplace that in the case where a part has to be treated, if certain parts of the part are not to be treated, for example by etching, deposition or the like, a screen is applied to those parts that are not to be treated, in the form of a coating of material to be removed later. In general, in cases where electrolytic deposition or etching constitute the treatments concerned, the coating is in the form of a mask which is applied to the printed circuit board or other part, which mask prevents the treatment fluid , generally liquid, to exert any chemical action, for example an attack or a deposit, on the article at the locations where the mask is applied. This is because the mask is generally applied selectively only to parts of the part not to be processed. Once the attack, deposition or other operation is completed, the mask is subjected to chemical treatment by

  the application of a solution so that it is removed chemically

  the room. In general, this solution is an acidic or alkaline solution that breaks down the mask and separates it from the workpiece, often while the workpiece is being transported through a solution spray chamber. In the past, many of these chemical solutions removing masks, coatings or the like, had a chemical structure that dissolve the mask in the solution. When this is the case, the mask material can accumulate in the solution until it reaches a concentration reaching an unacceptable level, in which case the solution can either be rejected,

  be subjected to a subsequent operation of regeneration

  ration. In the past, many of these masks were of the water-soluble type, which led them to

  to be rejected to the sewers, with the solutions.

  The greater consideration given to the environment has led to the development of other masks or coatings, some of which are not soluble in water, such as polymers and others, including

  masks that are not soluble in the solu-

  used to remove them from underlying parts such as printed circuit boards or others. Thus, although the chemicals used to separate polymers or other wafer masks or other parts are capable of rapidly removing masks from the pieces, they leave the material removed often in a range of physical states ranging from gelatinous to that of particles such as flakes or relatively inert films, which can remain in the solution

  almost indefinitely, without dissolving.

  With the increasing development of the electronics industry, an ever increasing demand has focused on the development of coin processing machines capable of high speed automatic processing, particularly on printed circuit boards and the like. This necessarily implies the requirement of high speeds for the treatment of films and debris resulting from the elimination of chemical etch resistances and deposition or masks of the panels. This necessarily results in a demand for higher processing speeds for the removal of accumulated residues from solutions that have been used to remove

the masks of the pieces.

  In the past, in most cases of filtration, the filtrate or filter cake is permeable, which allows the action of the filter to continue until the accumulation of the aggregate: z of the filtrate slows down the passage of the liquid to an inefficient level. For example, U.S. Patent No. 3,776,800 discloses a removable filter used to remove particles from a chemical etching solution. In addition, the removal of resistances and other masks of workpieces is described in US Pat. No. 4,015,706 which also mentions certain processing functions to which the present invention is directed.

  In the case of certain masks or cer-

  certain reserves, especially when they are made of polymer,

  the presence of dandruff, flakes, etc., which

  come from the polymer or other mask, can render the sieve or other filter inoperative, by closing or clogging it, because of the ability of these films or flakes to

  attach themselves to the sieve or other filter.

  When it is desired to separate particles from liquids, it is known to use certain forms of screens or filters for automatic cleaning, for example by vibration, so that the particles are removed by reverse flow techniques, or by interruption of work to allow the removal of particles from

  aggregate, in a general way.

  An apparatus for treating various articles, including printed circuit boards, to remove a mask or resist, or other coating, and to facilitate the regeneration of the chemically shrinkable solution. For this purpose, there is provided a separation apparatus comprising one or more sieves or filters can be traversed by the solution substantially free of particles, at the same time that this solution washes the sieve to prevent particles, flakes, etc.. accumulating in the pores of the sieve or filter, the particles thus removed from the sieve or filter by washing, then being collected,

  preferably so as to allow a period of

  next step, the particles being able to be sufficiently removed, by filtration, from a small part of the collected treatment solution, so that the solution can be reused, while most of the treatment solution is almost immediately ready for reuse. An apparatus for chemically removing particles of solids from a process liquid, the solid material from

  parts subjected to a chemical treatment with a liquid.

  The removal or removal of the solid material is carried out by a separation technique which uses filtration of the treatment liquid by passage through sieves or filter plates arranged angularly, which can be traversed by a downflow solution, while retaining particles which are subsequently removed from the screen by washing and collected, preferably during subsequent filtration of the washing liquid, which is

  also, preferably, the treatment liquid.

  The main object of the invention is therefore an improved apparatus for chemically removing solid material from parts being processed. The invention more particularly relates to an apparatus of this type in which a separation is performed on particles, debris, flakes, etc., present in the treatment liquid following removal of the solid material parts. To this end, the invention also relates to an improved separation apparatus which allows the flow of treatment liquid through a filter medium, and wherein the inlet surface of the filter medium is washed so that the particles are collected. For this purpose, the collection of particles is periodically triggered, means being provided to then further separate the treatment liquid particles so that the liquid can be reused. The apparatus is particularly suitable for processing printed circuit boards and sheets and the like by removing masks, resistances, coatings or the like with a chemical solution such as a stock removal solution. which is sprayed on the pieces, while they are transported along a certain path. For this purpose, one or more sieves are used, as well as sieve washing ducts intended to collect the debris and then to evacuate

these towards a collecting area.

  The invention also aims at concentrating

  remove particles to facilitate treatment.

  The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting example and in which: - Figure 1 is an end view of a reserve removal device according to the invention, seen in the scroll direction of parts in this apparatus, most of the solution flow paths being illustrated; - Figure 2 is a horizontal section

  part of the apparatus according to the invention, according to

  II-I of Figure 1, showing more clearly various separation features of the present invention; - Figure 3 is a vertical section

  part of the apparatus according to the invention, according to

  line III-III of Figure 1; - Figure 4 is a partial vertical section of the apparatus according to the invention, substantially along the line IV-IV of Figure 2, and showing more clearly the characteristics of screen washing and reverse flow; and FIG. 5 is a partial vertical section of the apparatus according to the invention, substantially along the

line V-V of FIG.

  Referring first to Figure 1 which shows, indicated generally at 10, the apparatus according to the invention for removing a mask, a reserve or other element of printed circuit boards, printed circuit boards or the like, this apparatus being associated with an etching or chemical etching apparatus, electroplating apparatus, or other chemical treatment apparatus. The apparatus 10 comprises a chamber 11 whose interior 12 is divided into an upper part 13 and a lower part 14. The chamber 11 is defined by end and outlet 15 and 16 end walls having respective openings 17 and 18 entry and exit. The sidewalls 20 and 21 define the sides of the chamber, except that a prolonged housing portion is formed on the remote side 22 of the apparatus 10 and is defined in part by a horizontal wall 23 and a vertical wall 24 of the bedroom. The elongated housing is designated by the numeral 25, below the wall 23. The chamber has a bottom 26 and a cover

removable 27.

  A carrier 28, in the form of bars and wheels, similar to those described in US Pat. Nos. 4,015,706 and 4,046,248, is used and is also advantageously driven by drive means. similar to those described in the aforementioned patents. In addition, the apparatus 10 may be constructed in a modular form to be joined at its ends, with immediately adjacent modules, as described in the last two patents cited, by the use of similar assembly techniques. , alignment and training. These techniques will not be described in detail. In any case, the conveyor mechanism 28 is adapted to carry a printed circuit board or other piece A in the direction of the

  arrow 30, as shown in FIG.

  Upper and lower spray collectors 31 and 32, each having a plurality of spray pipes 33 extending transversely of the apparatus, dispense process liquid to spray nozzles 34. These nozzles 34 are arranged so as to spray the chemical treatment liquid, as indicated at 35, on the pieces A as they pass between the nozzles, this liquid having the effect of detaching, by chemical action, the resist or other coating of the pieces. AT

S58078

  and remove it from the latter by lowering it with the treatment solution to two filter screens

36 and 37.

  The filter screens 36 and 37 are part of the separation device for separating the particles which have been removed from the pieces A. The screens 36 and 37 are mounted obliquely, as shown in FIG. 1, so as to form a sufficiently acute angle with vertical (advantageously 60 degrees) to permit the passage of large amounts of process liquid therethrough as this process liquid falls in the direction of the arrow 38 in FIG. 1. It is evident that the porosity of the screens 36 and 37 is chosen according to the expected size of the particles for a given removal operation. Suitable supports are provided for the screens 36 and 37 to maintain them in the preferred orientation, as shown in a V-arrangement, the sieves on both sides converging towards a

gutter 40.

  Two washing spray collectors, shown in FIG. 4, are fed with the same treatment liquid as the one performing the chemical removal, by means of a distribution line 39 and a suitable connection conduit 43. These collectors 41 and 42 respectively carry associated nozzles 44 and 45

  spraying, oriented to produce a pulverulent

  or to the surface of the screens 36 and 37, as illustrated in FIG. 4, to wash off the flakes, films and other particles which have been removed from the treated parts, this spraying having the effect of causing these particles in the gutter 40. The return of the solution, for example by the line 39, is important because it prevents the accumulation of the solution in the gutter 40, which could otherwise occur until sieves 36 and 37 that

  particles could then clog up.

  The channel 40 is formed by the lower supports 46 and 47 of the sieves 36 and 37. The latter

  in the same way comprise supports 48 and 50.

  It thus appears that the debris removed by washing the sieves 36 and 37 accumulates in the trough 40 which extends substantially along the length of the apparatus, between the opposite end walls 15 and 16, as shown in FIG. but the washing liquid (treatment liquid) can flow freely from the left end of the trough 40, as shown in FIG. 3, into a channel 51 from which it leaves via an outlet pipe 52 flow in the direction of the arrow 53 in Figure 1 to a centrifugal pump 54. The latter generally operates continuously and it forces the treatment fluid, which is thus brought to it, in a pipe 55 to return it to the collectors 41 and 42 by line 39, in the direction indicated by the arrow 56

in Figure 1.

  It should be noted that a valve 57 mounted on a pipe 58 and controlled by a coil 60 is in the closed position during this flow of the treatment fluid to the channel 51 and through the pump 54,

  as indicated above, so that at this stage of operation,

  fluid can not flow through line 58 and be returned through line 39 as

shown in Figure 1.

  As previously indicated, particles, debris and the like accumulate in the trough 40 during

  a pre-set duration or until a

  previously established statement appears. This condition can be the rise in the level of the liquid in the trough 40, which has the effect of triggering the evacuation of the gutter, but it is advantageously the flow of a given period of time, for example a number predetermined period of seconds, established by a suitable timer T. In all cases, in accordance with the parameters previously established,

  the evacuation of the gutter 40 is effected by the introduction

  abrupt discharge of a quantity of treatment liquid in the direction of the arrow 64 in FIG. 3, in a duct 63, so as to form means propelling the debris accumulated in the gutter, its right end, in the orientation of Figure 3, towards the left end, in the direction of the arrow 65, into the channel 51, the debris and the liquid exiting through the conduit 52 to the pump 54. At about the same time as it controls the sudden flow in the pipe 63, the timer T also acts via the coil 66 controlling the valve 67, which causes the circulation in the pipe 63 via the pipe 68, or otherwise also triggers the coil 60 via the power line 70 to open

  the valve 57 so that the discharge of the treatment liquid

  which contains the debris that has just been discharged from the trough 40, via the T-connector 72 of the duct 55, is directed to the left, as shown in FIG. 1, via the duct 58, in the direction of the arrow 71, thus borrowing the shortest path that opposes any resistance to the passage of debris and liquid of

  treatment of the gutter 40 in a filter apparatus 73

  through the conduit 74. Propulsion

  treatment liquid from the conduit 63 is also

  timed by the timer T, so as to last a predetermined time at the end of which the timer T commands the closing of the valve 67 via the line 66 and, almost simultaneously, the actuation of the coil 60 causes the closing of the valve 57, all these operations being performed after the passage of a sufficient time, previously established in the timer T, so that the discharged solids and the treatment liquid from the gutter 40 have passed the pump 54. Then, the discharge of the pump 54 is returned to the collectors 41 and 42 via the

leads 56.

  It should be noted that the pump 54 is driven by any suitable motor 75, suitably

mounted as shown in 76.

  It should also be noted that the process liquid passing through the screens 36 and 37 is collected at the bottom of the chamber 14 and is directed to a main pump (not shown) located in the casing extension of the lower portion of the chamber. chamber 14 to be recycled up the main line 77 distribution, in the direction indicated by the arrow 78 in Figure 1, to the main lines 80 and 81 distribution that feed the

  upper and lower collectors 31 and 32 of pulveri-

  respectively. It should also be noted that lines 80 and 81 include suitable flow control devices 82 and 83, generally in the form of valves, valves or the like, which can be

manually adjusted.

  With reference to FIG. 5, it will be noted that line 63, which supplies the large volume of propellant in the form of a treatment fluid to gutter 40, also provides an antifoam agent from a reservoir 91 defoamer, preferably by establishing a partial vacuum at the location of the junction of a conduit 92 with the pipe 63, this partial vacuum being transmitted by a valve 93 retaining or non-return (to prevent the liquid to flow to the left through it, as shown in FIG. 5), in order to suck the anti-foaming liquid 94 from the container 91, to mount it in a pipe 95, to pass it through a flowmeter 96, in a pipe 97 and through a check valve 93, under the effect of a partial vacuum or a venturi action, the antifoam agent thus being brought into the channel 40, with the treatment liquid

  which serves as propellant to evacuate the gutter.

  This is intended to prevent any formation of foam upstream of the pump 54, while the latter causes debris, particles or other, any cavitation of

the pump being thus prevented.

  The apparatus for separating the particles removed from the treatment liquid according to the invention

  also has an optional feature of

  flow version. These characteristics lie in the application of the treatment fluid to the opposite or lower faces of the screens 36, in a manner causing a vibration of the latter as well as the application of liquid to the sieves, upwards, which helps washing away particles, debris and the like from the upper surfaces of the sieves, the particles, debris and the like then falling into the gutter 40. The reverse flow is achieved by means of a pipe 100 connected to the pipe main 78 recycling, to an inlet port 101 opening into the interior of the chamber (Figures 1 and 4), o a flexible tube 102 transmits the treatment fluid to manifolds 103 and 104 distribution. These distribution manifolds 103 and 104 are mounted as indicated at 105 and 106, respectively, using any suitable techniques, below the trough 40, and they themselves carry rotary spray devices 107. These devices 107 have substantially the same embodiment, so that it suffices to

describe in detail one of them.

  Each spray device 107 is mounted on a liquid flow conduit 108 which receives process liquid from its appropriate manifold 103 or 104 and transmits it to a rotary head 110. The latter is rotated by the reaction pressure. processing liquid therethrough and the reaction pressure is used to rotate the head 110 and spray nozzles 111 and 112 it carries, so that the treatment liquid is sprayed from the nozzles 111 and 112 forming arcs which in fact sweep virtually all of the lower surface of the screens 36 and 37 (with the aid of eight nozzles), to thus perform the reverse flow washing removing particles from the

sieve 36 and 37.

  It should be noted, with reference to FIG. 1, that the filter 73 is equipped with a pipe 115 for discharging the treatment fluid allowing the passage of the treatment fluid which has been cleaned by filtration of the residues coming from the gutter, which filtration is performed in the filter 73, and this filtered treatment fluid is then directed by a line 115, in the direction of the arrow 116, to return to the chamber where it enters through the inlet 101. It should be noted that the flow of fluid in line 100 produces a partial vacuum or venturi effect in line 115 to return filtered fluid to the interior of the chamber. It also appears that in the case where the characteristic

  reverse flow of the invention should not be used.

  In this case, the sprayheads 107 do not receive liquid via line 102 and the treatment liquid can then be supplied continuously through line 100 into the chamber through which it enters the chamber. opening 101 to produce the action of

  venturi reducing the filter filtered liquid 73 through

  of conduct 115, or, alternatively, the opening of

  ture 101 can be modified to perform a discharge

direct in the crankcase.

  The filter 73 generally comprises a removable filter basket (not shown) in which debris gradually accumulate until they form a substantially dense cake which must then be removed by hand. This can be checked periodically, for example daily, according to the experience of the operators, and the filter basket can then be replaced or simply emptied for reuse. In the case where the filter 73 is not checked and the debris accumulate in the filtration chamber 73 at a level such that the filtration action can no longer take place and the liquid accumulates, a device suitable level limiting 120, sensitive

  level, can be operated to override the action

  the coil of the valve 67, 66, by means of a pipe 121, which makes it possible to intervene primarily on the evacuation of the trough 40 by the distribution of the treatment fluid through the pipe 63 in order to prevent the

  pumping debris, particles and other

  with the process fluid, pump 54 to filter 73 through line 74,

  until the filter 73 can be discharged.

  It goes without saying that many modifications can be made to the apparatus described and shown without departing from the scope of the invention. For example, although a slope angle of 30 degrees (with the horizontal) has proved advantageous, for sieves 36 and 37, in order to allow sufficient passage of the liquid through them, it is obvious that other angles can also give a satisfactory job. In addition, it should be noted that although sieves 36 and 37 are the preferred type

  separator filters at this location, others available

  filtration devices that are not, from the point of view

  technical, sieves, can also be used.

  Other details of the embodiment and operation of the apparatus according to the invention may also be modified

  without departing from the scope of the invention.

  It therefore appears that the object of the present invention is to prevent the formation of a deposit and the consequent clogging of filter screens, disadvantages of the previous embodiments. The present invention is particularly useful in the cases where the removed masks or coatings are made of polymers that tend to accumulate and dry on the surface of the filters, and the invention solves this problem by placing the screens in the chamber. treatment they can receive a large flow, for example 150 liters of solution per minute, to wash the sieves and keep them free of collected debris, this flow also preventing sieves from drying, which could otherwise cause adhesion of the polymer in the filtering medium in cases o

polymers are used.

Claims (16)

  Apparatus for chemically removing a solid material from articles (A) being chemically treated with a liquid, the apparatus comprising a treatment chamber (11), means (28) located in an upper part of the chamber and for supporting articles being processed, means (31, 32) for supplying the chamber with process liquid so that it is sprayed onto articles placed in the chamber so that a solid material is removed from said articles by spraying the treatment liquid, separating means located in the chamber and for separating a solid material from the treatment liquid, and collecting means placed inside the chamber and intended to collect the treatment liquid to recycle it to the distribution means, the apparatus being characterized in that it comprises filter means (36, 37) located in the separation means and arranged so as to at an angle sufficiently acute with the vertical to allow a treatment liquid to fall through these filtration means and the solid material, not passing through them, to be removed by washing to a residence zone, means ( 41, 42) for washing the filtration means in the separating means and for distributing a treatment liquid on the filtering means in order to wash out the solid material by entraling it towards the residence zone, means (40) for evacuation forming part of the separation means and for discharging the treatment liquid and the material solid from the living area.   2. Apparatus according to claim 1, characterized in that it comprises a secondary filter (73) connected to the evacuation means in order to receive the treatment liquid and solids and remove by   filtration the solids from the treatment liquid.   3. Apparatus according to claim 2, characterized in that it comprises means (52, 54, 55, 39) for returning the filtered treatment liquid means evacuation to the room.   4. Apparatus according to claim 1, characterized in that the living area comprises a gutter (40) for receiving the solids and the treatment liquid, a conduit (52) discharging being connected to the gutter and comprising means intended to receive the treatment liquid arriving in the gutter, and to recycle it to an upper part of the chamber, the   means of evacuation comprising a device (54) for   pulse for periodically passing a stream of treatment liquid in the gutter to evacuate accumulated solids.   5. Apparatus according to claim 2, characterized in that the living area comprises a gutter (40) for receiving solids and the treatment liquid, a discharge line (52) being connected to this gutter and comprising means intended to receive the treatment liquid arriving in the gutter, and to recycle it to an upper part of   the chamber, the means of escape including a   propulsion system (54) for circulating periodically   dique a stream of liquid in the gutter to evacuate the accumulated solids, the discharge means comprising a conduit (63) discharging from the gutter and carrying a valve (67), means (T) being operatively connected to the valve and the propulsion device so that, under the effect of the actuation of the latter, the valve is operated approximately simultaneously from a normal flow position between the discharge pipe and the chamber to another flow position between the discharge line and the secondary filter, so that the materials   accumulated solids are directed to the secondary filter. dary.   6. Apparatus according to one of the claims   1 and 5, characterized in that it comprises means (103,   104) placed in the chamber,   below the filtering means, elements (101, 102) connecting the flow inversion means to a source (78) of process fluid and said flow inversion means comprising a discharge element (107). treatment liquid for discharging the liquid from   treatment against the underside of the filament means   slanted in order to facilitate cleaning by removal of solids.   7. Apparatus according to claim 5, characterized in that it comprises means (91) for adding approximately continuously a antifoam agent to the treatment liquid. Apparatus according to claim 1, characterized in that the article support means comprises a device (28) for conveying the articles through the chamber at the upper part thereof in a substantially horizontal path, an elongated inlet opening (17) to an elongated outlet opening (18),   treatment liquid comprising spray nozzles (34)   located above and below the path, and the collecting means comprising a reservoir portion located at the bottom (26) of the chamber, - a pump (54) being associated with this reservoir part in order to return the treatment liquid to the spray nozzles, the filtration means comprising sieves (36, 37) and the washing means comprising spray nozzles (111, 112) arranged to spray the treatment liquid along the sieves.   9. Apparatus according to claim 1, characterized in that the filtering means comprise two screens (36, 37) each placed so as to form an acute angle   about 30 degrees with the horizontal.   10. Apparatus for processing platelets and printed circuit boards, and other similar articles (A) having polymer stock parts to be removed by means of a spray-removed resist removal solution on the articles while being carried on a path, the apparatus comprising a processing chamber (11), means (28) for conveying articles into the chamber for moving the articles from an opening (17) to a first end to a discharge opening (18) at the other end, spray nozzles (34) disposed within the chamber for spraying the solution onto the articles, means for separating the particles solution of the solution, and a collecting zone located in the chamber and intended to collect the solution for recycling to the nozzles, the apparatus being characterized in that it comprises at least one screen (36 or 37) f the portion of the separation means and arranged to form a sufficiently acute angle with the vertical to allow the solution to fall through it at the same time as the reserve particles are separated by sieving, the reserve particles not passing through the sifter being removed from the latter by washing, to a gutter (40), at least one screen-cleaning nozzle (111 or 112), which forms part of the separation means, being arranged substantially at the upper end of the sieve in order to applying a spray on the latter and removing by washing the reserve particles which are directed towards the gutter, discharge means, which are part of the separation means, being intended for   evacuate the solution and particles from the gutter.   Apparatus according to claim 10, characterized   in that it comprises a filter (73) connected to the evacuation means and intended to receive the solution and the   particles from the gutter.   Apparatus according to claim 10, characterized   in that a discharge pipe (52) is connected to the gutter in order to return the solution of the gutter to the chamber, the discharge means comprising a   propulsion device (54) for periodically providing   only to the gutter a current of sufficient solution   to evacuate the accumulated particles.   Apparatus according to claim 11, characterized   characterized in that a discharge conduit (52) is connected to the gutter to return the gutter solution to the chamber, and in that the discharge means comprises a propulsion device (54) for periodically providing to the gutter a stream of solution sufficient to evacuate the accumulated particles, the discharge means comprising a pipe (63) discharging from the gutter and carrying a valve (57), means (T) being operatively connected to the valve and the propulsion device, so that, under the effect of the actuation of the propulsion device, the valve is operated approximately simultaneously from a normal flow position between the discharge line and the chamber to another flow position between the discharge line and the filter so that the particles   accumulated are directed periodically to the filter.   Apparatus according to claim 13, characterized   in that it includes a pipe (115) for   return the filtered solution from the filter to the chamber.   15. Apparatus according to claim 10, characterized   in that it comprises flow inversion means (103, 104) placed in the chamber below the filtering means, elements (101, 102) connecting the flow inversion means to a solution source (78) and flow inversion means having at least one rotating solution nozzle (111 or 112) placed below the screen to spray the solution upwardly through the screen, to promote the cleaning of the latter by moving the particles along said sieve.   Apparatus for separating flakes, particles or other material from a chemical solution which is brought into contact with articles (A) for treatment by removing the material from a chamber (11), the separating apparatus being characterized in that it comprises a filtering medium (36, 37) placed in the chamber and on which the solution containing the material removed is applied, this filtering medium eliminating by filtration the material of the solution, on at least one surface of said filter media, means (103, 104) for washing the surface of the filter medium by removing the removed material for passage into a residence zone, means (107) for discharging the   material removed from the living area.