DE102017206943A1 - Process for cleaning filter cloths and plates of a filter press - Google Patents

Abstract

The present invention relates to a method of cleaning filter cloths and any filter membranes of a filter press, wherein: (a) several used filter plates are lifted out of the filter press together by a load handler attached to a hoist and in a cleaning bath for cleaning the filter cloths and, if necessary, membranes are laid down, (b) immediately thereafter new filter plates are jointly inserted into the filter press by means of a load-handling device attached to a hoisting gear in order to replace the previously removed filter plates.

Description

The present invention relates to a method for cleaning filter cloths and plates and any existing membranes of a filter press.

In precious metal processing or recovery (for example, in the treatment of spent catalytic converters), valuable noble metal salts or complexes of aluminum salts or other non-noble metal salts are separated by, for example, pH-induced precipitation and downstream filtration. For filtration, e.g. Filter presses are used.

Filter presses are pressure filters used for the solid-liquid separation of suspensions. Types of filter presses well known to those skilled in the art are chamber filter presses, frame filter presses and membrane filter presses. A filter press contains a larger number of filter plates, which are arranged parallel to each other and to each of which at least one filter cloth and possibly at least one filter membrane is / are attached. For the filtration process, the filter plates are pressed together. For this, e.g. the filter plates are arranged between a fixed end plate and a movable end plate and via a mechanical or hydraulic pressure device which acts on the movable end plate, the compression of the filter plates takes place. Each filter plate is slidably mounted on horizontal side guides, for example via laterally attached to the plate supporting elements, so that the filter plates can slide on each other. By a sufficiently high contact pressure, the tightness of the filter pack is ensured. When the filtration process is complete, the pressure is released, the filter press is opened and the filter cake is removed from the filter cloths.

At regular intervals, the filter cloths and plates and, if applicable, existing membranes must be cleaned with a suitable cleaning solution.

It is known that for the purpose of cleaning the filter cloth, washing nozzles pass between the filter plates and spray the filter cloths with a cleaning liquid. In the DE 3520571 A1 a filter press is described in which the filter cloth of each filter plate can be held by suitable positioning elements both in a spread position for better removal of the filter cake and in a voltage applied to the filter plate position for the treatment with the washing nozzles.

During the washing step, the filter plates remain in the filter press. During this period, the filter press is not available for operation.

Depending on the chemical nature of the filter cake residues, the cleaning of the filter cloths, plates and optionally membranes can be very time-consuming. If the filter press, for example, used for the precious metal treatment or recovery, the treatment of the filter cloths, plates and any existing membranes is usually carried out with an acidic cleaning solution, which can take several hours to complete.

On the website httpfig // www.mse-filterpressen.de / de / opt-filterpressefiltertuchsauern.html a static and a dynamic cleaning of the filter cloths are described. During static cleaning, the acid cleaning solution applied in a mixing station is pumped into the filter press. The acid acts on the filter plates and filter cloths for about 16 hours. In the case of dynamic cleaning, an acidic cleaning solution circulates through the filter plates and filter cloths of the filter press via a pump. This shortens the cleaning time to about 2 hours. For both variants, however, the filter press is not available for operation for the duration of the filter cloth cleaning.

If a manual removal of the filter cloths to be cleaned from the filter plates in order to put them in a cleaning bath and after cleaning again attach to the filter plates, this is also very time consuming and leads to a failure of the filter press during the filter cloth cleaning.

An object of the present invention is the cleaning of the filter cloths, plates and optionally membranes of a filter press on an efficient process that keeps the operating failure of the filter press very low and yet causes the most complete removal of the filter cake residues. The cleaning of the filter cloths, plates and optionally membranes should therefore be as effectively integrated into the operation of the filter press, so that a cleaning-related failure of the filter press is minimized, but this is not at the expense of cleaning efficiency.

• (a) mehrere gebrauchte Filterplatten durch ein Lastaufnahmemittel, das an einem Hebezeug befestigt ist, gemeinsam aus der Filterpresse herausgehoben und in einem Reinigungsbad zur Reinigung der Filtertücher-, -platten und ggf. -membranen abgelegt werden,
• (b) unmittelbar anschließend neue Filterplatten durch ein Lastaufnahmemittel, das an einem Hebezeug befestigt ist, gemeinsam in die Filterpresse eingesetzt werden, um die zuvor herausgenommenen Filterplatten zu ersetzen.

This object is achieved by a method for cleaning filter cloths, plates and optionally membranes of a filter press, which contains a plurality of filter plates, to each of which at least one filter cloth and optionally at least one filter membrane is mounted, wherein:

• (a) several used filter plates are lifted out of the filter press together by means of a load handling device attached to a hoist and deposited in a cleaning bath for cleaning the filter cloths, plates and, if appropriate, membranes;
• (b) immediately thereafter insert new filter plates together by a load handler attached to a hoist into the filter press to replace the previously removed filter plates.

In the context of the present invention, it has been recognized that filter plates of conventional filter presses can be very easily removed from the filter press via hoists (such as a crane, for example) and one or more load handling attachments attached thereto and also reinserted. In a single step, the load handler can pick up several or all of the filter plates (e.g., 15-100% of all filter plates present in the filter press) and settle in a standing cleaning bath. Since then immediately new filter plates (i.e., filter plates on which cleaned or still unused filter cloths and possibly membranes are attached) are used by a hoist with a load-carrying means back into the filter press, it comes only to a very short-term breakdown. After inserting the new filter plates, the operation of the filter press can be resumed. At a later date, the removal of filter plates to be cleaned and their immediate replacement by new filter plates using a hoist with load handling means again, so that, for example, all the filter plates (or the attached filter cloths or membranes) are subjected to a cleaning without further that this leads to longer interruptions of the filtration process.

The filter press can be a chamber filter press, a frame filter press or a membrane filter press. These filter press types are well known to those skilled in the art.

Depending on the medium to be filtered, the number of filter plates in the filter press can vary over a wide range. For example, the filter press contains 20-200, 30-160 or 40-140 filter plates. The filter plates are e.g. around plastic filter plates. Other materials are also usable. When selecting the material, make sure that it is not attacked by the cleaning solution.

The inventive method is suitable for both relatively small and relatively large filter plates. For example, the filter plates may have a dimension (length × width) of 20-200 cm × 20-200 cm.

In a known manner, at least one filter cloth and possibly at least one filter membrane are attached to each filter plate. If e.g. When using two filter cloths per filter plate, one of the cloths may be attached to the front of the filter plate while the second cloth is attached to the back of the plate.

Each filter plate is preferably slidably mounted on horizontal side guides in the filter press via laterally attached to the plate support elements, so that the filter plates can slide on each other. The filter plates are therefore mounted on their side-mounted support elements on the horizontal side guides of the filter press and can be moved along these side guides. In order to ensure the most secure possible resting of the filter plates on these horizontal side guides, the support elements are preferably on the side guides over. This embodiment of the filter plates is basically known to the person skilled in the art. As will be described in more detail below, in an exemplary embodiment of this supernatant of the support elements can be used on the side guides to receive the filter plates with the load-receiving means and lift out of the filter press.

As already stated above, several used filter plates are lifted out of the filter press together by a load-handling attachment which is attached to a hoist and deposited in a cleaning bath for cleaning the filter plates incl. Filter cloths and possibly membranes.

Used filter plates are to be understood as those whose filter cloths and, if appropriate, membranes are already so heavily soiled or coated with filter cake residues that purification is required (because, for example, the filtration properties are no longer sufficiently good).

The hoist is for example a crane or a swivel arm device. Connected to the hoist (for example, the crane) are one or more load-carrying means which receive the filter plates to be cleaned, including filter cloths, and lift them out of the filter press.

A suitable load-carrying means is for example a traverse (eg a support beam), a gripper, a pair of pliers or clamp, a loading fork, a hook harness or a lifting magnet. Since the load-receiving means can come into contact with the cleaning liquid (eg a dilute acid) when the filter plates are deposited in the cleaning bath, they are preferably made in these contact areas made of a material that is not attacked by the cleaning fluid. Optionally, the load-receiving means may be provided in these areas with a coating (eg, an acid-resistant coating) which is resistant to the cleaning liquid.

The support beam may, for example, be a profile beam (for example with a U, L or T profile). When the profile beam is a section steel and an acidic cleaning fluid is used, the section steel preferably has an acid resistant coating (e.g., a plastic coating).

In an exemplary embodiment, the load-carrying means comprises two support beams (for example profiled beams) spaced parallel to one another, on each of which a longitudinal beam is attached in the middle, which are in turn connected to one another via a transverse bar. By way of this crossbeam, for example, the load-handling device can be connected to a crane (for example by means of a crane hook). The distance between the two support beams in the load-receiving means is selected so that the filter plates to be lifted out rest at least partially on the two support beams (for example via the support elements attached laterally to the filter plates). When lifting the lifting device by the hoist then the filter plates are raised and can be removed from the filter press.

The load-receiving means may, for example, receive the filter plates via their laterally mounted support elements. When lifting out the filter plates, e.g. the support elements at least partially rest on the load receiving means. As already mentioned above, the filter plates are usually mounted on their side-mounted support elements on horizontal side guides in the filter press and can be moved along these side guides, the support elements preferably projecting on the side guides. At this supernatant of the support members, the load handling means (e.g., a support beam) may be attached to lift the filter plates out of the filter press.

In order to achieve a cleaning of all filter plates in as few passes, the load-receiving means is preferably designed so that it can accommodate a relatively large number of filter plates and take out together in one step from the filter press. If, for example, a support beam is used, this can be achieved over a sufficiently long length of the beam.

For example, 10-100% or 15-40% of the filter plates present in the filter press are taken out of the filter press together by the hoist with the load-handling device attached thereto and deposited in the cleaning bath for cleaning the filter plates, filter cloths and possibly membranes.

The filter plates to be lifted out of the filter press by the load suspension means may be e.g. act around the filter plates, which are already in use at this time for the longest and therefore can be assumed that they have the largest contamination of the filter cloth and possibly existing membranes.

The cleaning bath is preferably positioned in sufficient proximity to the hoist, so that a problem-free laying of the filter plates is possible.

In the cleaning bath is a cleaning liquid. The choice of a suitable cleaning liquid depends on the nature of the filter cake residues to be removed and can be made by a person skilled in the art on the basis of his specialist knowledge. If the filter press is used, for example, for the precious metal recovery or treatment, for example, an acidic, aqueous cleaning liquid is used.

The filter plates are preferably deposited in the cleaning bath in such a way that the soiled filter cloths and, if present, membranes are substantially completely immersed in the cleaning liquid. When placing the filter plates, the cleaning liquid may already be present in the bath. Alternatively, it is also possible for the cleaning fluid to be introduced into the cleaning bath only after the filter plates have been deposited. If plastic filter plates (e.g., polypropylene) are used, there is a risk that they will float due to their low density on the cleaning fluid and thus prevent complete immersion of the soiled filter cloth and the possibly existing membrane. In order to prevent floating of the filter plates, a device for locking or fixing the filter plates may be attached to the cleaning bath. This locking device is e.g. around a Arretierungsbalken that secures the filter plates after they are deposited in the cleaning bath against floating.

As stated above, immediately following the removal of the used filter plates, new (i.e., cleaned or still unused) filter plates are put together in the filter press by load handling means attached to a hoist.

Under new filter plates are understood as those to which cleaned or still unused filter cloths and possibly membranes are attached.

With regard to the preferred properties of the hoist and the lifting device attached to it can be made to the above statements.

In the context of the present invention, it is possible that the removal of the used filter plates and the immediate subsequent insertion of the new filter plates with one and the same hoist or load-carrying takes place. Alternatively, it is also possible that two separate hoists, to each of which a load-receiving means is attached, are used for the removal of the used filter plates and the insertion of the new filter plates. In the latter variant, the operational failure of the filter press can be further minimized, however, the provision of a second hoist (e.g., a second crane) is associated with additional costs.

The number of newly inserted filter plates preferably corresponds to the number of previously removed filter plates, although this is not mandatory. In the context of the present invention, it is in principle also possible that the number of newly inserted filter plates and the number of previously removed filter plates are different, provided that this does not adversely affect the desired filtration performance of the filter press.

The cleaning of the filter cloths and any existing membranes using a lifting device attached to a hoist such. a crane is very effectively integrated into the operation of a filter press, so that a cleaning-related failure of the filter press is minimized, but this is not at the expense of cleaning efficiency.

• – vor Schritt (a) die folgenden Schritte (i), (ii) und optional (iii), in denen (i) eine Suspension in der Filterpresse filtriert wird, so dass sich auf den Filtertüchern und ggf. vorhandenen -membranen jeweils ein Filterkuchen bildet, (ii) der Filterkuchen von den einzelnen Filtertüchern und ggf. vorhandenen -membranen entfernt wird, (iii) optional die Schritte (i) und (ii) ein- oder mehrmals wiederholt werden,
• – und nach Schritt (b) eine ein- oder mehrmalige Wiederholung der Schritte (i), (ii), (iii), (a) und (b).

In a preferred embodiment, the method according to the invention comprises

• - before step (a), the following steps (i), (ii) and optionally (iii), in which (i) a suspension in the filter press is filtered, so that in each case a filter cake on the filter cloths and any existing membranes (ii) the filter cake is removed from the individual filter cloths and any membranes present, (iii) optionally steps (i) and (ii) are repeated one or more times,
• - and after step (b) a one or more repetition of steps (i), (ii), (iii), (a) and (b).

In an exemplary embodiment, the suspension is a noble metal-containing suspension (containing, for example, noble metal salts and / or complexes). In this case, the filtration of the suspension is preferably carried out for the precious metal recovery or treatment.

As already mentioned in the introduction and generally known to the person skilled in the art, the filter plates are pressed together with sufficiently high pressure during the filtration (ie during step (i)), while for the removal of the filter cakes (ie in step (ii)) the pressure on the Filter plates was drained again, so that each filter plate or the attached filter cloth and the possibly existing membrane is easily accessible from the outside. The lifting of the used filter plates and the insertion of new filter plates via the hoist is carried out in the pressure-free state or at least in a state of relatively low external pressure (i.e., no or little mechanical or hydraulic pressure applied to the filter plates).

Optionally, steps (i) and (ii) may be repeated one or more times until a condition is reached in which at least some of the filter cloths or membranes have sufficiently high level of soiling or a sufficiently high level of filter cake residue. Then, step (a) is carried out in which a plurality of used filter plates are lifted out of the filter press together via at least one load handling device and deposited in a cleaning bath, followed by step (b), in which several new filter plates are inserted into the filter press by a load handling means to replace the previously used used plates.

The sequence of steps (i), (ii), (iii), (a) and (b) may be repeated one or more times.

If, for example, 25% of the filter plates present in the filter press are removed in step (a), after three repetitions of steps (i), (ii), (iii), (a) and (b) all the filter plates or the Filter cloths and, if appropriate, membranes attached thereto have been subjected to a cleaning treatment.

• – eine Filterpresse, die eine Vielzahl von Filterplatten enthält, an denen jeweils mindestens ein Filtertuch und ggf. mindestens eine Filtermembran angebracht ist,
• – zumindest ein Hebezeug, an dem ein Lastaufnahmemittel angebracht ist,
• – einen Reinigungsbehälter zur Aufnahme einer Reinigungsflüssigkeit, wobei das Hebezeug so positioniert und ausgelegt ist, dass es mehrere Filterplatten aus der Filterpresse herausheben und in dem Reinigungsbehälter ablegen kann.

Furthermore, the present invention relates to a system comprising

• A filter press which contains a multiplicity of filter plates, on each of which at least one filter cloth and possibly at least one filter membrane are attached,
• At least one hoist to which a load-handling device is attached,
• - A cleaning container for receiving a cleaning liquid, wherein the hoist is positioned and designed so that it can lift a plurality of filter plates from the filter press and store in the cleaning container.

With regard to the preferred characteristics of the filter press, the filter plates, the filter cloths and membrane, the hoist, the Lifting means and the cleaning container can be made to the above statements.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3520571 A1 [0005]

Cited non-patent literature

• httpfig // www.mse-filterpressen.de / en / opt-filterpressefiltertuchsauern.html [0008]

Claims (11)

 Process for the cleaning of filter cloths and possibly filter membranes of a filter press, which contains a multiplicity of filter plates, on each of which at least one filter cloth and possibly at least one filter membrane are mounted, wherein: (A) several used filter plates by a lifting device, which is attached to a hoist, lifted out of the filter press together and placed in a cleaning bath for cleaning the filter cloths and possibly membrane, (b) immediately thereafter insert new filter plates together by a load handler attached to a hoist into the filter press to replace the previously removed filter plates. The method of claim 1, wherein the filter press is a chamber filter press, a frame filter press, or a membrane filter press; and / or the filter press contains 20-200 filter plates. The method of claim 1 or 2, wherein the hoist is a crane or a swing arm device; and / or the load-carrying means comprises a cross member (e.g., a support beam), a gripper, a pair of pliers or clamp, a loading fork, a hook harness or a lifting magnet. Method according to one of the preceding claims, wherein the support beam is a profile beam with U, L or T-profile. Method according to one of the preceding claims, wherein the filter plates each have laterally mounted support elements and these support elements when lifting the filter plates at least partially rest on the load receiving means.  Method according to one of the preceding claims, wherein 10-100% of the filter plates present in the filter press are lifted out of the filter press together by the load-receiving means and deposited in the cleaning bath.  Method according to one of the preceding claims, wherein a locking device is attached to the cleaning bath, which secures the deposited filter plates against floating in the cleaning liquid.  Method according to one of the preceding claims, wherein in steps (a) and (b) the same hoist and the same load-handling means is used.  The method of any one of the preceding claims, further comprising Before step (a), the following steps (i), (ii) and optionally (iii), in which (i) a suspension is filtered in the filter press so that a filter cake is formed on the filter cloths and, if appropriate, membranes, (ii) the filter cake is removed from the individual filter cloths and optionally membranes, (iii) optionally repeating steps (i) and (ii) one or more times, - and after step (b) a one or more repetition of steps (i), (ii), (iii), (a) and (b).  The method of claim 9, wherein the suspension is a noble metal-containing suspension and the filtration of the suspension for the noble metal recovery or treatment takes place. Plant comprising A filter press which contains a multiplicity of filter plates, on each of which at least one filter cloth and possibly at least one filter membrane are attached, At least one hoist to which a load-handling device is attached, A cleaning container for holding a cleaning liquid, wherein the hoist is positioned and adapted to lift a plurality of filter plates from the filter press and place them in the cleaning container.