Patent Description:
In particular, the invention relates to an abatement filter for removing the solid particulate present in the air which comes out of the leather treatment chambers, and more particularly of the leather spray chambers.

It is known that in order to treat the leathers, and in particular to deposit one or more layers of paint on the relative surfaces, the leathers themselves are made to pass through a chamber, in which they are sprayed with the paints themselves. The paints are substantially nebulized by means of nozzles, until drops of micrometric or smaller dimensions are obtained, which largely adhere to the surface of the skin, creating the required layer. At the same time, part of the drops remain suspended in the air, forming a potentially harmful and/or toxic aerosol. These paints may contain polluting and/or toxic materials, and therefore cannot simply be dispersed into the environment but must be previously filtered.

In particular, depending on the country in which the production line is located, the air emitted by the same must comply with specific laws. In particular, in Italy the air must comply with Legislative Decree no. <NUM> of <NUM> April <NUM> concerning environmental regulations.

Similarly, machinery that can release potentially harmful emissions into the environment must fall within the UNI EN ISO <NUM>-<NUM>: <NUM> standard.

Filters are known which provide for aspirating and filtering the air present inside the environment where the leathers are sprayed with at least one chemical substance, for example in order to deposit on their surface a protective and/or decorative layer, for example a colored layer.

In particular, these filters are divided into two types: dry filters and water filters.

The water filters provide for the positioning of a plurality of nozzles configured to spray water or other liquids on the aerosol emerging from the spray chamber, in order to precipitate the liquid and/or solid suspension present in the aerosol.

However, said known filters are not fully satisfactory since the water which is sprayed must be further treated before it can be disposed of. Furthermore, this type of filtering is not sufficiently effective for suspensions smaller than <NUM>, and in particular it is almost completely ineffective for particles smaller than <NUM>.

Furthermore, dry filters, also known as labyrinth filters, are known, which provide for the aerosol to pass through a plurality of small-sized channels obtained in a filtering layer, so that the suspension is deposited on the surface of the channels themselves.

However, even said dry filters are not fully satisfactory as they easily saturate and need to be periodically replaced. This is particularly undesirable since in order to replace them it is necessary to interrupt the operation of the scrubber filter, and in some cases of the entire production line, if it is not possible to isolate it from the filter. Furthermore, the dry abatement filters are usually vertical and are raised above the ground, generally at a height of a few meters, thus making the removal operations complex. Furthermore, they are not effective in the filtration of small particles.

Blast chillers are also known which provide for the use of a filter element made of paper, fabric, or non-woven fabric (TNT), to be positioned along the aerosol path, generally in correspondence with the apex of the abatement filter, in order to at least partially trap the suspended particulates.

However, these filters are not fully satisfactory since, similarly to what happens in dry filters, they can become saturated and consequently lose effectiveness. This in particular translates into a reduction in the aerosol flow that can pass through and consequently be filtered.

Therefore it is necessary to periodically replace the filtering elements, but this, as already mentioned, involves the need to shut down the production line or at least to isolate the spray chamber, with the obvious undesirable consequences. Furthermore, the replacement of the filters is particularly complicated since the abatement filters usually have an accentuated vertical development, and therefore the filtering element may not be easily reachable by a user.

In order to overcome this drawback, solutions have already been proposed that provide for a pair of coils of a ribbon of the material of which the filtering element is made, positioned on the sides of the abatement filter, with the ribbon running along the vertical of the filter itself or horizontally according to the embodiment, so as to cover the outlet of the output channel. In this way, since the filtering element is substantially constituted by a continuous belt, it is possible to replace the filtering surface simply by sliding the belt without having to leave the exhaust of the abatement filter uncovered, so as not to have to turn off the production plant.

However, even this solution is not completely satisfactory as it requires the space on the sides of the abatement filter to house the coils, which can measure even more than one meter in diameter, and this is not always possible, since in factories usually the different processing stations are as close together as possible in order to reduce the space occupied by the production line. Furthermore, if the coils are positioned at ground level, it is necessary to protect them from dirt that can affect the filters before they are used.

It is possible to solve this problem by positioning the coils in an elevated position, but this entails a plurality of drawbacks; in particular, the coils are quite heavy and must be firmly secured to the Abatement filter. Furthermore, when it is necessary to replace them, it is necessary for the user to climb a ladder to remove them, with possible risks of falling, or in any case with strong risks for his safety.

<CIT> describes a scrubbing filter which is used for the aerosol produced by the leather coloring chambers and which is left in position during the whole operation of the apparatus.

The object of the invention is to propose an abatement filter and a method for its use which overcome the drawbacks of the known solutions.

Another purpose of the invention is to propose an abatement filter that allows emissions to be reduced within the law, and in particular the rules established by Legislative Decree No. <NUM> of <NUM> April <NUM>.

Another purpose of the invention is to propose a Abatement filter that is suitable for the UNI EN ISO <NUM>-<NUM>: <NUM> standard.

Another object of the invention is to propose an abatement filter and a method which allow to continuously monitor the state of the filter.

Another object of the invention is to propose an abatement filter and a method that can be implemented in a production line.

Another object of the invention is to propose a scrubber filter which has reduced horizontal dimensions.

Another object of the invention is to propose an abatement filter which does not require additional space for the filtering elements and/or for their replacement.

Another object of the invention is to propose an abatement filter and a method which allow to reduce the frequency with which it is necessary to replace the filtering element.

Another object of the invention is to propose a scrubber filter which allows to reduce the consumption of water.

Another object of the invention is to propose an abatement filter which is highly automated.

Another object of the invention is to propose an abatement filter and a method which are simple and quick to implement.

Another purpose of the invention is to propose an abatement filter and a method that allow to perform an effective filtration of the outgoing air, and in particular that allows to reduce the quantity of particulate present in the air below <NUM>/m<NUM>· h.

Another object of the invention is to propose an abatement filter which is effective in the filtration of particulate matter with dimensions lower than <NUM>.

All these objects, whether considered alone or in any combination thereof, and others which will emerge from the following description are achieved according to the invention with a device as defined in claim <NUM>, a production line as defined in claim <NUM>, and with a method as defined in claims <NUM> or <NUM>.

The present invention is further clarified hereinafter in some of its preferred embodiments, given purely by way of non-limiting example with reference to the attached drawings, in which:.

The abatement filter <NUM> according to the invention can be integrated into a leather processing line, and preferably it can be positioned in the vicinity of a leather treatment chamber, and in particular in the vicinity of a chamber, in which the leathers are sprayed at least a liquid substance, in order to achieve a suitable surface treatment. This in particular generates an aerosol <NUM> comprising a solid and/or liquid particulate in suspension in the air, which must be filtered before the air can be introduced into the environment outside the production line.

The spraying chamber (not shown) is connected to the abatement filter <NUM> by means of an inlet duct <NUM>. In particular, the inlet duct <NUM> is configured to allow the passage of the aerosol <NUM>, in particular in a direction D. The inlet duct <NUM> ends inside a container <NUM> which substantially defines the abatement filter <NUM>. Advantageously, in the operating condition, the container <NUM> can be substantially closed and isolated from the outside except for the inlet duct <NUM> and an outlet duct <NUM>, as will become clear later. Conveniently, the inlet duct <NUM> can represent the passage used by most, and preferably by all, the aerosol <NUM> to pass from the spray chamber to the external environment E.

As can clearly be seen from the figures, the container <NUM> has a substantially vertical development, at the in order to limit the horizontal dimensions inside the production line in which it is inserted.

Advantageously, the leathers are never inside the container <NUM>.

Advantageously, the container <NUM> can be external and separate from the processing line along which the leathers pass.

The inlet duct <NUM> can be fluidically connected to a suction device configured to generate a flow of fluids, and in particular of aerosols <NUM>, from the spray chamber towards the inside of the container <NUM> and subsequently towards the outlet duct <NUM>. Preferably said suction device can be positioned inside the container <NUM>, or, alternatively, it can be positioned outside the container <NUM> but be fluidically connected with it.

In particular, the suction device can be constituted by a centrifugal impeller <NUM>, driven by a motor <NUM>.

Advantageously, the outlet duct <NUM> can have a substantially smaller section than that of the container <NUM>, in order to facilitate the exit of said aerosol. <NUM> from the container itself.

The abatement filter comprises a liquid filter, indicated as a whole with the number <NUM>.

In one embodiment, the liquid filter <NUM> comprises at least a first nozzle <NUM> positioned inside the inlet duct <NUM> configured to spray a first liquid on said aerosol <NUM>, so as to achieve a first abatement of the particulate present in suspension. Advantageously, the first nozzle <NUM> can be positioned in equi-flow or counter-flow with respect to the aerosol flow <NUM> inside the inlet duct <NUM> in order to improve its filtering efficiency. Alternatively, the first nozzle <NUM> can be in equi-flow if the nozzle has a small diameter, so as to limit its clogging.

Preferably, the first liquid sprayed by the first nozzle <NUM> can be water.

In one embodiment, a plurality of first nozzles <NUM> can be present, which can be positioned, according to the direction of advance of the aerosol, substantially in sequence, or substantially in parallel.

Advantageously, a fan <NUM> configured to direct the aerosol flow <NUM> upwards can be present at and/or near the end of the inlet duct <NUM> which leads into the container <NUM>. Preferably the fan <NUM> is of the radial type.

Conveniently, at its internal end, the inlet duct <NUM> has an opening which allows the aerosol <NUM> to diffuse inside the container <NUM>, thanks to the action of the fan <NUM>, and also allows the solid and/or liquid particulate to fall down.

In one embodiment, in the lower position, and preferably on the bottom of the container <NUM>, there is a water recovery system, indicated as a whole with the number <NUM>.

The water recovery system <NUM> comprises a sludge deposit basin <NUM>, in which the solid and/or liquid particulate that falls from the inlet duct <NUM> is deposited.

In said basin <NUM> there is a pump <NUM> configured to pump the water present inside the basin itself towards the nozzles that make up the liquid filter <NUM> present in the abatement filter <NUM>, and in particular the first nozzle <NUM>, or other nozzles, as will become clearer hereinafter.

In a preferred embodiment, a suitable filter <NUM> can be provided on the suction side of said pump <NUM>, configured to block the solid components from the outside, in order to prevent clogging of the nozzles.

Furthermore, the scrubber filter <NUM> can comprise a suitable sludge recovery and/or disposal system <NUM>.

In one embodiment, the liquid filter <NUM> can comprise at least a second nozzle <NUM>, and preferably a plurality of second nozzles <NUM>, positioned in position higher than the end of said inlet duct <NUM> and configured to spray a fluid, preferably said first liquid, and more preferably water, in counter-flow with respect to the direction of advance of said aerosol <NUM>. In one embodiment, said second nozzles <NUM> can be fed by said water recovery system <NUM>, for example by means of a conduit <NUM>, which starts from said pump <NUM>, and which preferably can be the same conduit that also feeds the first nozzle <NUM>.

Advantageously, the inlet duct <NUM> it can occupy only a part of the section of the container <NUM>, so as to allow the fluid sprayed by said second uge IIi to fall and be collected in said basin <NUM>.

The abatement filter <NUM> comprises a dry filter, indicated as a whole with the number <NUM>. In particular, the dry filter is configured to allow the passage of the aerosol <NUM> through a plurality of small passages in order to allow the solid and/or liquid particulate to be deposited.

The dry filter <NUM> is arranged downstream from the liquid filter <NUM> with respect to the forward motion of the aerosol <NUM> inside the abatement filter <NUM>.

In one embodiment, the dry filter <NUM> can comprise at least one body filter filling body <NUM>, configured to perform a first dry filtration of the aerosol <NUM>. Advantageously, the filling body filter <NUM> can comprise a layer of filling bodies <NUM>, for example balls or complex objects with curved and/or flat surfaces, preferably made of plastic material with a rough surface, which trap the solid particles that are suspended in the aerosol <NUM>. Conveniently, said filling bodies <NUM> can be contained inside a suitable casing <NUM>. Advantageously, said dry filter <NUM> can be provided with one or more third nozzles (not shown), which allow to wash the filling bodies <NUM>, in order to remove the particles and solids deposited on their surface.

In one embodiment, the dry filter <NUM> can comprise, downstream of said filler bodies <NUM> filter <NUM>, one or more labyrinth filters <NUM>, configured to pass the aerosol <NUM> through a plurality of narrow passages, in order to to cause condensation of the liquid and/or solid suspension present in said aerosol on the walls of the passages of the filter <NUM>. Preferably these labyrinth filters <NUM> can be made of metal sheet.

The outlet duct <NUM> can be placed downstream of said labyrinth filters <NUM> and can have a smaller section than the rest of the container <NUM>, in order to improve the upward flow of aerosol <NUM>.

In a preferred embodiment, upstream of said outlet duct <NUM> there is a filtering apparatus <NUM>, configured to filter the aerosol <NUM> destined to exit the abatement filter <NUM> through said outlet duct <NUM>.

The filtering apparatus <NUM> comprises at least one laminar filter element <NUM>, having laminar shape - ie in which two dimensions, i.e. length and width, are much greater than the thickness, i.e. the dimension which is substantially transverse to the direction of the aerosol flow <NUM> - made in flexible filter material, for example in fabric, or in TNT, preferably obtained starting from natural or vegetable fibers, or in filter paper. Alternatively, the filter element <NUM> can be made of metal fibers, or of plastic fibers.

The filter element <NUM> has dimensions length and width - substantially corresponding to those of the container section <NUM>. Preferably the filter element <NUM> can have larger dimensions than the section of the outlet duct <NUM>, so as to allow covering the duct itself, and in particular it can have dimensions equal to twice the section of the outlet duct.

The filter element <NUM> has a size greater than half of the section of the container <NUM>, in order to allow adequate filtration of the aerosol <NUM>.

The filter element <NUM> has a dimension less than twice the section of the container <NUM>, in order to achieve effective aerosol filtration but at the same time to avoid excessive waste of space.

It is conveniently understood that, if the container <NUM> has an irregular and/or variable section, the filter element has dimensions between half and double the section of the container <NUM> in correspondence with the portion in which the filter element itself is positioned.

In a preferred embodiment, the filtering apparatus <NUM> comprises a movement assembly <NUM> configured to move said filter element <NUM> between a first operating position and a second rest position. Said first operating position is a position in which said filter element is located between the spraying chamber and the external environment, and is positioned in correspondence with the passage mainly traveled by the aerosol in order to exit the spraying chamber towards the external environment E. In said first operative position the filter element <NUM> is located in correspondence with the section of said outlet duct <NUM>, in order to filter the aerosol <NUM> exiting said outlet duct <NUM>. The second rest position is a position in which said filter element is not located between the spraying chamber and the external environment, and is not positioned in correspondence with the passage mainly crossed by the aerosol in order to exit the spraying chamber towards the external environment E. In said first operative position the filtering element <NUM> is in a first position in which it is available and/or reachable by a user for its replacement, and it is not in a position to filter the aerosol <NUM> exiting said outlet duct <NUM>.

In a preferred embodiment, said second position can be along one of the sides of the container <NUM>, and preferably it can be along a side perpendicular to the arrival side of the inlet duct <NUM>. Advantageously, said second position can be at a height that can be easily reached by a user.

In substance, therefore, the movement assembly <NUM> can be configured to make the filter element <NUM> travel a first horizontal section, in order to remove it from said first operating position, and a second vertical section, in order to bring it to correspondence with said second rest position.

In a preferred embodiment the container <NUM> can comprise a suitable slot <NUM> configured to allow the passage of said filter element <NUM> between said first and said second position.

In one embodiment the filter element <NUM> can be associated, preferably in a reversible manner, to said movement assembly <NUM> by means of a support structure <NUM> which comprises a plurality of support elements <NUM> configured to associate said filter element <NUM> to said movement assembly <NUM>. For example, said support elements can comprise a plurality of guides, or a plurality of gripping elements, for example a plurality of grippers, or a plurality of buttons. Conveniently, said support elements can in turn be associated with a frame (not shown) associated with said movement assembly.

Advantageously, the support structure <NUM> is integral with the filter element <NUM>, and in particular can be moved by the movement assembly <NUM> between a first position in which the filter element <NUM> is in a position suitable for filtering the aerosol <NUM>, and a second position in which the filter element <NUM> is in a position not suitable for filtering the aerosol <NUM>. In particular, said second position can be a position in which the filter element <NUM> can be easily separated and/or re-associated with the support structure <NUM>, in order to be replaced.

Advantageously, said support structure <NUM> is configured to associate said filter element <NUM> with movement means <NUM>, consisting for example of a pair of conveyor belts or, preferably of a pair of chains <NUM>, <NUM>', which can be closed-loop, or open, for example, with winding at both ends. Said movement means <NUM> are configured to move said support elements <NUM>, and therefore said filtering element <NUM>, between said first and said second position. In one embodiment, said support elements <NUM> can be associated with said chains <NUM>, <NUM>'by means of suitable pins.

Advantageously, there may also be suitable transverse support elements <NUM>, positioned between the two chains <NUM>, <NUM>', in order to support the filter element <NUM>.

In an embodiment with said chains <NUM>, <NUM>', a closing element <NUM> of the slot <NUM>, for example made of sheet metal, can be positioned in a more rearward position - ie closer to said second position with respect to said filter element, ie further upstream with respect to said filter element <NUM> in the displacement that goes from said second position at said first position -.

In one embodiment said chains <NUM>, <NUM>'are moved by at least one actuator <NUM>. Conveniently the motion generated by said actuator <NUM> can be transmitted to the two chains <NUM>, <NUM>' by means of suitable transmission means. Advantageously, said actuator <NUM> can comprise an electric motor.

Advantageously, said actuator <NUM> can be connected to a suitable control and processing unit (not shown).

Advantageously, said chains <NUM>, <NUM>'are closed-loop, and are configured to be returned around a roller, preferably idle, positioned inside said container <NUM>.

Furthermore, said chains can be supported by at least one suitable guide element positioned in correspondence and/or in proximity of the opening <NUM> or in any case at the intersection between the substantially vertical section crossed by the movement means <NUM>, and the substantially horizontal section, in order to allow the two chains <NUM>, <NUM>'to perform the angle.

In one embodiment the guide element can be a cylinder, in order to allow the sliding of the filter element. Advantageously, the transverse guiding element can be Teflon-coated, or in any case coated with a non-stick material.

Advantageously, the guide element can provide at the ends a pair of toothed wheels configured to engage the links of the chains <NUM>, <NUM>'. Preferably, in this case, the transverse guiding element can have a diameter smaller than that of the toothed wheels so as to substantially not come into contact with the filtering element <NUM>.

In a further embodiment, said at least one guiding element can only be shown by the pair of toothed wheels which in this case can be rotatably secured by suitable mechanical means to the outer wall of the container <NUM>.

In one embodiment, said movement means <NUM> can be configured to move said support structure <NUM> and/or said filter element <NUM> from said first position, in which the filter element is in a position suitable for filtering the aerosol <NUM> exiting said container <NUM>, to said second position, in which the filter element is in a position not suitable for filtering the aerosol <NUM> leaving said container <NUM>, and to a third position, in which the filter element <NUM> is in a position, which preferably is different from said second position and is not suitable for filtering the aerosol <NUM> exiting said container <NUM>. For example, said third position can be on a side that can be facing and/or angled with respect to that on which said second position is located.

Advantageously, said third position can be substantially symmetrical with respect to said second position and in particular it can be positioned at the same height as said second position. Advantageously, the distance that the filter element <NUM> must travel between said first position and said second position and vice versa can be equal to the distance that the filter element must travel between said first position and said third position and vice versa.

In one embodiment there may also be a further filter element <NUM>', preferably associated with a further support structure <NUM>'.

In an embodiment, said further filter element <NUM>'can be connected to said movement assembly <NUM>. Alternatively, said further filter element can be associated with a further movement assembly <NUM>'.

Advantageously, said further filter element <NUM>'can be substantially similar to said filter element <NUM>.

Advantageously said further movement assembly <NUM>' can be substantially similar to said movement assembly <NUM>. Preferably said further movement assembly <NUM>'can be configured to move said further filter element <NUM>'between a further first position, in which the further filter element <NUM>' is positioned in a position suitable for filtering the aerosol <NUM> exiting said container <NUM>, a further second position, in which the further element filter <NUM>'is positioned in a position not suitable for filtering the aerosol <NUM> exiting said container <NUM>, and a third position, which is preferably different from said second position and in which the further filter element <NUM>' is positioned in a position not suitable for filtering the aerosol <NUM> exiting said container <NUM>.

Advantageously said further first position can face said first position, and preferably in a higher position than said first position. Alternatively, said further first position can be in a lower position than said first position. Advantageously, said further second position can correspond to and/or be placed side by side and/or facing said second position. Advantageously, said further third position can correspond to and/or be placed side by side and/or facing said third position.

In an embodiment, said further movement assembly <NUM>'can be associated with said container on a face which substantially faces the surface on which said movement assembly <NUM> is positioned. In a further embodiment said further movement assembly <NUM>' can be associated with said container on a surface which is substantially angled with respect to the surface on which said movement assembly <NUM> is positioned.

In one embodiment at the first position, and preferably just above said first position and/or said further first position a grid can be positioned, for example made of metal, configured to prevent the filter element <NUM> from bending upwards under the thrust of the aerosol flow <NUM>.

In one embodiment, the abatement filter <NUM> comprises at least one sensor of pressure <NUM>, and preferably at least one pair of pressure sensors pressure <NUM>, <NUM> configured to measure the pressure along the aerosol path <NUM>.

In particular, a first pressure sensor <NUM> can be positioned upstream of said filter element <NUM>, while a second pressure sensor <NUM> can be positioned downstream of said filter element.

Preferably, both pressure sensors <NUM>, <NUM> can be connected to the control and processing unit which controls the operation of the scrubber filter <NUM>.

Advantageously, said control and processing unit can be configured to calculate the pressure variation upstream and downstream of said filter <NUM>, in order to verify the proper functioning of the filter itself. Advantageously, moreover, said control and processing unit can be configured to calculate the derivative of the pressure variation over time.

Advantageously, said control and processing unit can be configured to send an alarm signal to a user if it detects a malfunction and/or detects saturation and/or clogging of the filter element <NUM>. Advantageously, depending on the extent of the malfunction, they can be sent different signals.

The operation of the abatement filter <NUM> is clear from what has been said above.

In particular, the aerosol <NUM> coming from the spraying chamber is sucked by the suction device through the inlet duct <NUM>, where it receives a first spray of water from the first nozzle <NUM>.

Subsequently, the fan <NUM> directs it upwards.

The second nozzles <NUM> spray a further jet of water onto the aerosol, in order to remove a further fraction of liquid and/or solid suspension.

The water sprayed by the first nozzles <NUM> and/or the second nozzles <NUM> is collected in the basin <NUM>, filtered by the filter <NUM> and conveyed by the pump <NUM> through the conduit <NUM> back to the first nozzles <NUM> and/or the second nozzles <NUM>.

Thereafter the aerosol <NUM> can pass through the dry filter <NUM>, releasing a further fraction of the liquid and/or solid suspension on the walls of said dry filter.

Subsequently, the aerosol <NUM> can enter the outlet channel <NUM> and pass through the filter element <NUM> in order to release a further fraction of liquid and/or solid suspension.

In particular, in this case the suspension is trapped in the cavities present in the filter element <NUM>, which can gradually become saturated, until it no longer allows the passage of the aerosol <NUM>.

Advantageously this can be detected by the control and processing unit on the basis of the pressure measurements carried out by sensors <NUM>, <NUM>.

If, for example, the pressure difference upstream and downstream of the filtering element is lower than a predefined value and/or selected by the user, the control and processing unit can be configured to send an alarm signal, informing that the filter element is clogged and requires maintenance or needs to be replaced.

Advantageously, if the variation in pressure difference measured by said pressure sensors <NUM>, <NUM> is faster than a predetermined rate and/or selected by the user, the control and processing unit can be configured to send a different signal.

Advantageously, following the signal, the user can stop the operation of the production line and/or of the spraying chamber and/or of the abatement filter <NUM>, and subsequently activate the movement assembly <NUM> in order to replace the filter element <NUM>. In in particular, the actuator <NUM> which activates the movement means <NUM> can be activated. In particular, in this way the filter element <NUM> is removed from said first operating position and moved towards said second rest position.

Conveniently if the guide element comprises a transverse cylinder, said filter element <NUM> can be configured to rest on the cylinder itself during the passage from said horizontal section to said vertical section, thus depositing on the guide element a part of the suspension which had been filtered. Advantageously, if the guide element comprises a Teflon-coated cylinder, the deposited suspension may not stick and fall to the ground.

When the filter element <NUM> is in said second position, the user can easily remove it from the movement assembly by acting on the support elements <NUM>. Alternatively, said support elements <NUM> can be connected to said control and processing unit in order to allow the their control in an automated way.

Subsequently, the user can reactivate the movement assembly <NUM> in order to move said filter element <NUM> from said second position to said first position.

Conveniently, when said filter element <NUM> is in said first position, the closing element <NUM> is located in correspondence with the slot <NUM> substantially closing it.

Subsequently, the user can reactivate the Abatement filter and/or the spray chamber and/or the production line.

Advantageously, after having been removed the filter element <NUM> can be washed in order to be reused.

Alternatively, in the embodiment in which the further filter element <NUM>'is present, the movement assembly <NUM> is configured to move the filter element between said first, said second and said third position, and the operation is as follows.

When the filter element <NUM> which is in said first position is saturated, the further filter element <NUM>'can be associated with the movement assembly in said second or said third position.

Subsequently, said movement assembly <NUM> can be operated in order to move said filter element <NUM> towards said third or said second position, and in particular towards the position in which said further filter element <NUM>'has not been associated. Advantageously, this movement of the movement means <NUM> involves simultaneously the movement of said further filter element <NUM>'from said second or said third position up to said first position. In this way, the time during which there is no filter element <NUM>, <NUM>'in said first position can be considerably reduced, and therefore the time during which the filtration of the aerosol <NUM> in output from the abatement filter <NUM> does not take place, and this allows to reduce the time during which it is necessary to stop the filtering booth.

In the embodiment in which the further filter element <NUM>'and the further movement assembly <NUM>' are present, the operation is as follows.

The further filter element <NUM>'is associated with the further movement assembly, for example by means of the further support structure <NUM>', in said further second or in said further third position, and preferably in said further third position. Subsequently, the further actuator is operated in order to move the further movement means <NUM>'in order to transfer the further filter element <NUM>' from said further second or said further third position to said further first position.

Subsequently, the movement assembly <NUM> is operated in order to move the filter element <NUM> from said first position to said second or to said third position. Subsequently, the filter element <NUM> can be detached and replaced.

Advantageously, in this way it is possible to completely eliminate the time in which there is no filter element <NUM>, <NUM>'upstream of said outlet duct <NUM>, and therefore it is not necessary to stop the machine and/or the production line.

Claim 1:
Abatement filter (<NUM>) to filter the aerosol (<NUM>) produced in a leather treatment and/or finishing chamber, said abatement filter (<NUM>) comprising a container (<NUM>), through which the aerosol (<NUM>) to be filtered is passed, said container (<NUM>) containing:
- at least one suction device (<NUM>,<NUM>) configured to suck the aerosol (<NUM>) generated in said leather treatment and/or finishing chamber,
- at least one liquid filter (<NUM>) configured to spray at least one water-based liquid on said aerosol (<NUM>) in order to at least partially precipitate the particulate present in suspension in the aerosol itself,
- a dry filtering apparatus (<NUM>) arranged downstream of said liquid filter (<NUM>) according to the direction of flow of said aerosol (<NUM>), comprising at least one laminar filter element (<NUM>),
characterized in that said at least one element filter (<NUM>) is movable, in a mechanized way, between a first operating position suitable for filtering said aerosol (<NUM>), wherein said first position is interfering with the path of said aerosol (<NUM>) through said container (<NUM>), and a second non operating position not suitable for filtering said aerosol (<NUM>), wherein said second position is not interfering with said path.