METHOD FOR CLEANING A FILTER IN A FILTER UNIT AND FILTER UNIT WITH A FILTER HOUSING

Description

field of technology

[0001] The invention relates firstly to a method for cleaning a filter in a filter device with a filter housing and the filter located therein, wherein the filter device has a removable filter material collection chamber in which filter material that accumulates during the cleaning of the filter is transferred.

[0002] The invention also relates to a filter device with a filter housing and a filter located therein, wherein the filter device has a removable filter material collection chamber in which filter material that accumulates during the cleaning of the filter is transferred. State of the art

[0003] In metal printing equipment, such as laser sintering or laser melting systems, and also, for example, so-called 3D laser printing systems, it is known to supply process gas to the cabin of the printing equipment in a recirculating process, which is cleaned or regenerated in a filter device with regard to impurities (e.g., soot) that arise during the metal printing process, especially due to the high heat exposure, and which can arise particularly from the laser application.

[0004] The production of a die-casting part in the metal pressure device preferably takes place in a protective gas atmosphere created by the process gas. Typically, an inert gas such as argon or nitrogen is used as the process gas, or alternatively, argon or nitrogen alone. However, a mixture of gases, particularly inert gases, can also be used as the process or protective gas. Generally, the aim is for the atmosphere, especially within the chamber, to contain no or practically no oxygen. Therefore, in the case of the metal pressure device, the medium flowing through the filter system is the process gas.

[0005] Depending on the size and / or complexity of the printed item to be produced, such a printing process can easily extend over several hours or even several days.

[0006] A metal pressure device is known, for example, from DE 10 2017 206 792 A1. In connection with a filter device, such a metal pressure device is known, for example, from DE 20 2012 013 036 U1. A method for cleaning a filter is known from DE 10 2015 118 746 A1. Furthermore, a filter device of the type in question and a method for cleaning the filter are described in DE 10 2019 132 349 A1.

[0007] The filter material collected during filter cleaning typically consists of a highly reactive material. Consequently, there is an increased risk of ignition when this filter material leaves the protective atmosphere created by the process gas during disposal.

[0008] In this context, it is known, particularly in smaller systems, to use disposable filters that are discarded once a predetermined fill level is reached. It is also known to flood disposable filters, especially those with a larger capacity, with water and / or oil, thereby passivating the filter material. After this, the disposable filter can be removed from the housing and disposed of. The housing is then cleaned and fitted with a new disposable filter.

[0009] Solutions are also known in which a fire retardant, such as lime or gas granules, is continuously blown into the filter housing, so that the entire surface of the filter is wetted and mixes with the material filtered out. During the cleaning process, this filter material-fire retardant mixture is transferred to a filter material collection chamber. However, this results in a relatively large amount of waste, necessitating relatively frequent emptying of the filter material collection chamber.

[0010] Cleaning the filter by spraying it with oil is problematic with regard to disposal.

[0011] From DE 10 2020 102 034 A1, a device and a method for cleaning a filter are known. Only the filter material collection chamber is provided, which can be a disposable container intended for single use. The filter material is not treated for reactivity before entering the collection chamber.

[0012] Furthermore, a device and a method for cleaning a filter are known from DE 10 2017 207 415 A1. In this process, the filter material is placed untreated into a collection container and then fed into a treatment chamber downstream of the collection container.

[0013] From the unpublished WO 2021 / 151 938 A1 it is known with regard to the method for cleaning a filter and the filter device to use a gas stream for transporting the filter material from the filter into the reaction chamber.

[0014] In a method known from the unpublished WO 2021 / 151 681 A1 for cleaning a filter and a corresponding filter device, it is known to use only gravity to transport the filter material into the collection chamber. Summary of the invention

[0015] Starting from a prior art such as that given by DE 10 2020 102 034 A1, the invention aims to improve a method and a filter device of the type in question, in particular with regard to filter cleaning, taking into account the typically high reactivity of the filter material.

[0016] To solve the problem, it is essential to first introduce oxygen for passivation, whereby the oxygen is blown into the room or alternatively drawn into the room by applying a corresponding negative pressure, whereby the oxygen is introduced via atmospheric air and at the same time a turbulence of the filter material in the room is carried out, and furthermore, that the atmospheric air is used both for passivating the filter material and for transporting it to the collection chamber by blowing the filter material out of the reactor room.

[0017] Upstream of the filter material collection chamber, in the direction of transfer of the filter material, a separable space can be provided in which the cleaned filter material is treated with regard to reducing any remaining reactivity, in which the filter material is swirled in the space, and in which the filter material collection chamber is removed from the filter device after a certain time, in particular after several cleaning cycles, and the contents are disposed of.

[0018] With regard to the filter device, the problem is solved by the subject matter of claim 6, in particular in that the filter material collection chamber is detachable from the filter device after a cleaning cycle in order to dispose of the contents and atmospheric air can be introduced into the room, wherein, in addition to passivation, turbulence and also a transfer of the filter material into the filter material collection chamber can be carried out by means of the atmospheric air.

[0019] According to the proposed method and the proposed design of the filter system, passivation of the filter material cleaned by the filter is achievable before it is transferred to the filter material collection chamber. This allows for targeted passivation to be carried out in the designated, reactor-like, separable space, integrated into the filter cleaning cycle and the cleaning process.

[0020] The treatment of the filter material, to be carried out in the preferably airlock-type partitioned space, can be performed to such an extent that the filter material is completely or almost completely passivated with regard to its reactivity. Alternatively, such treatment can lead only to partial passivation, so that when the treated filter material is transferred to the filter material collection chamber, a comparatively low level of reactivity may still be present. In this case, a subsequent passivation of the filter material can occur automatically in the filter material collection chamber as a result of the treatment previously carried out in the partitioned space.

[0021] The space designated for this purpose can be separated from the filter housing containing the filter. For example, a valve, possibly controlled by a vacuum, can be provided to create such a separation. Opening the valve allows filter material, possibly previously removed from the filter during the cleaning process, to be transferred from the filter housing into the reactor space.

[0022] Preferably, a relatively small amount of filter material is passivated in this room, and preferably the amount of filter material that accumulates during a cleaning process.

[0023] The chamber provides temporary storage for the highly reactive filter material, for treatment before transferring it to the filter material collection chamber, in particular to reduce its reactivity. During this treatment, the filter provided in the filter housing can advantageously continue to be used to filter the process gas flowing through the metal pressure device until a preferably predetermined filter material intake volume is reached again.

[0024] Over time, especially over several cleaning cycles, the filter material that accumulates in the filter material collection chamber can finally be disposed of in the simplest way by emptying the collection chamber and, if necessary, transferring it to a transport container or the like, due to the previously carried out passivation of the filter material.

[0025] In one possible embodiment, the treatment of the filter material in the separable chamber can be carried out by introducing oxygen. The filter material is preferably brought into contact with oxygen in a controlled manner within the reactor chamber. The oxygen can be blown into the chamber or, alternatively, drawn into the chamber by applying a corresponding negative pressure. The reaction with the oxygen achieves the passivation of the filter material.

[0026] The filter material collection chamber, which receives the essentially passivated filter material, is preferably filled with atmospheric air, so that after the transfer of the filter material, which has been exposed to oxygen in the room, into the collection chamber, a post-reaction, such as smoldering under atmospheric air, can occur. With conventional manufacturing processes, such as 3D metal laser printing, sufficient time remains for such a post-reaction, since the next cleaning cycle typically introduces new filter material into the collection chamber after about 6 to 48 hours.

[0027] According to a preferred method, the oxygen is introduced via atmospheric air. Thus, according to one possible embodiment, ambient air can be drawn in or blown in to passivate the filter material temporarily stored in the chamber.

[0028] To further improve the passivation of the filter material in the chamber, it can be provided that, preferably simultaneously with the introduction of oxygen, the filter material is swirled within the chamber. This results in improved contact between the filter material surface and the oxygen, and thus an improved reaction. The passivation of the filter material can therefore potentially be completed in a shorter time compared to passivation without swirling.

[0029] According to a preferred embodiment, the turbulence can be achieved by introducing oxygen or atmospheric air. The separable reactor chamber can have labyrinthine flow paths that lead to the desired turbulence.

[0030] Furthermore, the introduction of oxygen or atmospheric air, and the resulting preferably also turbulence, can achieve not only passivation but also the transfer of the filter material into the filter material collection chamber. In a preferred embodiment, the preferably introduced atmospheric air serves both to passivate the filter material and to transport it into the collection chamber by blowing the filter material out of the reactor space.

[0031] Through a targeted reaction with atmospheric oxygen, the filter material is passivated to such an extent that any risk during disposal is eliminated. The filter material collection container is filled only with the passivated filter material and atmospheric air, allowing for disposal by simply emptying the container. Furthermore, after emptying and repositioning within the filter unit, the container is ready for operation without any further preparations, such as evacuation or refilling procedures.

[0032] The filter material collection chamber can have a usable intake volume of approximately 5,000 to approximately 15,000 cm³, but possibly also up to 20,000 cm³ or more.

[0033] For example, during a cleaning cycle, a filter media volume of approximately 15 to 25 cm³ can be generated after about 10 to 14 operating hours, preferably about 20 cm³ after 12 operating hours. Assuming a maximum permissible filling of the filter media collection chamber with approximately 3,000 cm³ of filter media, this results in approximately 120 to 200 permissible filter cleaning cycles, or 1,500 to 2,000 operating hours, as the replacement or emptying interval for the collection chamber. In filter systems with, for example, two parallel filter units, the time between cleaning cycles doubles, so that, with, for example, 120 to 200 permissible cleaning cycles per filter unit, a total operating time of 3,000 to 4,000 hours is achieved, meaning that each container only needs to be removed and emptied after 3,000 to 4,000 hours.With 7-day operation of the entire system and 90% availability, it is advantageous that a collection chamber only needs to be emptied every 6 months. Brief description of the drawings

[0034] The invention is explained in more detail below with reference to the accompanying drawing, which merely represents an exemplary embodiment. It shows: Fig. 1 in a schematic perspective view of a metal pressure device with an associated filter module, comprising several filter devices; Fig. 2 in a perspective view of the arrangement of three filter devices connected in parallel in terms of flow, with a recirculating fan and a medium cooler; Fig. 3 a schematic sectional view through a filter device along line III-III in Figure 2 , concerning a process step for filtering a medium flowing through the filter device; Fig. 4 a sectional view according to Figure 3, however, concerning an offset cutting plane; Fig. 5 one of the Figure 3 corresponding sectional view through the filter device, relating to a process step for evacuating the interior of a filter housing; Fig. 6 a subsequent view to Figure 5 , relating to a process step for cleaning a filter in the filter housing of the filter device and collecting the separated filter material in front of a sluice valve; Fig. 7 the enlargement of area VII in Figure 6 ; Fig. 8 one of the Figure 7 corresponding illustration, concerning a subsequent situation after opening the sluice valve and transferring the filter material into a separable space interposed between the filter housing and a filter material collection chamber; Fig. 9 a subsequent illustration to Figure 8, concerning the passivation of the fill material temporarily stored in the space and the transfer of the fill material into the filter material collection chamber; Fig. 10 a further sectional view, concerning a situation and transfer of the passivated fill material into the collection chamber; Fig. 11 the reactor interposed between the filter housing and the filter material collection chamber, having the separable space, in a perspective view; Fig. 12 the reactor in a longitudinal sectional view; Fig. 13 the reactor in a further longitudinal sectional view; Fig. 14 the filter material collection chamber removed from the filter device in an arrangement position on a transport vehicle; Fig. 15 a subsequent view to Figure 14 after turning the filter material collection chamber into an emptying position; Fig. 16 a subsequent illustration to Figure 15after lifting the filter material collection chamber; Fig. 17 a situation during the process of moving the filter material collection chamber to a disposal container using the transport vehicle; Fig. 18 a situation during the process of docking the filter material collection chamber to the disposal container; Fig. 19 the emptying situation; Fig. 20 a schematic sectional view through the filter device according to Figure 3 , after repositioning the emptied filter material collection chamber on the filter unit. Description of the embodiments

[0035] The presentation and description initially refers to Figure 1 , a metal printing device 1 with an associated filter module 3 comprising a plurality of filter devices 2.

[0036] The metal printing device 1 essentially comprises a cabin 4 in which the metal printing process can be carried out. Here, a desired component is produced layer by layer from fine metal powder using selective laser melting under the influence of a laser beam. Production can be carried out directly from so-called 3D CAD data, enabling the manufacture of fully functional components from high-quality metals.

[0037] Besides the in Figure 1 The laser device 5, which is only shown schematically, is essentially an application device for applying a layer of metal powder, part of the printing device, and also a powder storage container and a powder collection container into which excess powder can be wiped off.

[0038] The metal part is manufactured in a completely enclosed cabin 4, which may optionally be equipped with a door 6 or the like that closes the cabin 3.

[0039] Regarding the manufacturing process, reference is made, for example, to the DE 10 2017 206 792 A1 cited at the beginning.

[0040] During the printing process, the atmosphere in the cabin 3 is preferably regenerated. For this purpose, a gaseous process gas 7, preferably a protective gas such as argon or nitrogen, is preferably blown into the cabin 4 and simultaneously extracted using a recirculation method. A blower 8, for example a recirculating blower, is preferably used for this purpose. The blower 8 can be a so-called side-channel blower or the like.

[0041] In the illustrated embodiment, the blower 8 is arranged in the filter module 3 in spatial proximity to the filter devices 2.

[0042] With regard to the method for cleaning the filter as well as the design of the filter device, reference is made to the aforementioned DE 10 2019 132 349 A1. The content of this patent application is hereby fully incorporated into the disclosure of the present invention, also for the purpose of including features of this patent application in the claims of the present invention.

[0043] As further details can be seen in the schematic representation in Figure 1 As can be seen, the blower 8 is flow-connected to the interior of the cabin via a pressure line 9 and a suction line 10 as well as an inlet 77 and an outlet 78.

[0044] Here, the pressure line 9, starting from the blower 8, can be connected directly, if necessary, as in Figure 2As shown, the pressure line 9, with an intermediate medium cooler 11, leads into the cabin 3, preferably to a ceiling area of ​​the cabin 3. During operation, the pressure flow of the medium 7 in the pressure line 9 follows a direction a.

[0045] At least one filter device 2 is integrated into the suction line 10, corresponding to a line upstream of the blower 8 in the direction of flow of the process gas 7. According to the illustrated embodiment, several filter devices 2, here three, can be provided.

[0046] The filter devices 2, together with the blower 8 and the optionally provided medium cooler 11, and optionally with a pre-separator and / or a fine filter, can be arranged together in the filter module 3. This filter module 3 can have a filter housing 14 which includes the aforementioned elements. Only two interfaces are required, one each for the pressure line 9 and the suction line 10.

[0047] A pre-separator, if provided, can be located upstream of the single filter unit 2 or upstream of the multiple filter units 2 when viewed in the direction of flow of the process gas 7, while the fine filter can be located downstream of the filter unit 2 in the direction of flow.

[0048] In suction line 10, a typical manufacturing process and the associated process gas circulation result in a direction b of the suction flow.

[0049] The filter devices 2 are preferably provided in substantially identical configurations, each having a medium inlet 15 and a medium outlet 16. Each filter device 2 is preferably directly connected to the suction line 10 via its respective medium inlet 15. The medium outlets 16 of the filter devices 2 open into a suction transfer line 17, which, optionally with the interposition of the fine filter, leads to the blower 8 (see in particular...). Figure 2 ).

[0050] The fine filter can, for example, also be provided at the end of the pressure line 9 in the direction of flow, and possibly also in the direction of flow after the medium cooler 11.

[0051] The Figures 3 and 4Each figure shows a vertical section view through one of the filter devices 2 in regeneration mode, in which the medium 7 discharged from the cabin 4, for example contaminated by soot, is filtered, with reference to the usual operating position of the filter device 2.

[0052] As for example from the sectional view in Figure 3 As can be seen, the filter device 2 can have an approximately circular cylindrical filter housing 18, with a circumferential housing wall 19 and a housing roof 20. The housing bottom 21 can be funnel-shaped with a central bottom opening 22, to which a reactor section 23 and a filter material collection chamber 24, which can be removed from the filter housing 18, can be connected in a transfer direction g of a filter material 32.

[0053] A lock valve 51 is arranged between the filter housing 18 and the space 49 formed in the reactor section 23, which is loaded into a shooting position by a compression spring 50.

[0054] On the underside of the housing cover 20, a filter 26 projecting into the interior 25 of the filter housing 18 can be arranged, as shown. The filter wall of this filter can be, as also shown, tubular or circular-cylindrical, with a central longitudinal axis x that, in the usual arrangement, is aligned along a vertical line. According to the illustrated embodiment, the longitudinal axis x of the filter 26 can simultaneously form the central longitudinal axis of the entire filter housing 18.

[0055] The filter 26 is surrounded at a distance from the outer surface 28 of the filter wall 27 by a guide wall 29, preferably oriented concentrically to the longitudinal axis x. This guide wall 29, like the filter 26, is suspended from the underside of the housing roof 20 and preferably connected to it in a flow-tight manner. The annular space 35 between the guide wall 29 and the filter wall 27 is open in the axial direction towards the interior 25, while the corresponding end face 30 of the filter 26, which faces downwards during normal operation, is designed to be impermeable to the flow, in particular to the process gas 7. Filter material 32 separated in this way can fall by gravity alone through the bottom opening 22 of the housing bottom 21 into a channel section 52 that extends into the space 49 of the reactor section 23.This channel section 52 is initially closed in the area of ​​the end facing away from the interior 25 of the filter housing 18 by a valve plate 53 of the lock valve 51.

[0056] The inlet opening 31 of the medium inlet 15 can, preferably, be provided in the housing wall 19, so that an at least approximately tangential flow of the medium 7 into the interior 25 of the filter housing 18 can occur, thereby initially achieving a vortex-like pre-separation of filter material 32 (compare Figure 3 The filter device 2 initially acts in the manner of a cyclone separator, in which the process gas flow is guided in a vortex-like manner from the inlet opening 31 in the annular space resulting between the guide wall 29 and the housing wall 19.

[0057] The outlet opening 33 of the medium outlet 16 can be provided in the area of ​​the housing ceiling 20 according to the illustrated embodiment, in particular, and preferably, centrally, receiving the longitudinal axis x and further associated with the filter interior 34 enclosed by the filter wall 27.

[0058] As a result of the suction flow that occurs during normal operation (filter operation) of the filter device 2, the process gas 7 drawn into the interior 25 is, after the vortex-like deflection, directed downwards towards the front surface 30 of the filter 26 and drawn from below into the annular space 35 between the filter wall 27 and the guide wall 29, resulting in a penetration of the filter wall 27 from the outer surface 28 to the inner surface 36 of the filter wall 27 (see arrows d in Figure 4 ), so that the filtered medium 7 reaches the filter interior 34 and leaves the filter device 2 via the outlet opening 33 (compare Figure 4 ).

[0059] Filter material 32 separated in this process may be adhered to the filter wall 27. Any filter material 32 falling through the annular space 35 during this filtration process is preferably collected in the filter material collection chamber 24.

[0060] As can be seen from the sectional views, for example in the Figures 3 and 4The medium inlet 15 and the medium outlet 16 can each be equipped with a shut-off valve 37 and 38, respectively, to isolate the filter unit 2 from the regeneration process by isolating it from the suction line 10 and the suction transfer line 17. In this state, the regeneration of the process gas 7, while the metal pressure unit 1 remains in operation, is handled solely by the other filter units 2 of the filter module 3. This ensures at least nearly continuous operation of the metal pressure unit 1 even in the event of a failure or deliberate isolation of a filter unit 2, for example, for cleaning.

[0061] For this purpose, the preferably pneumatically actuated shut-off valves 37 and 38 of the medium inlet 15 and the medium outlet 16 are moved into a closed position. The control of the shut-off valves 37 and 38 can, preferably, be effected via control electronics 39 (not shown in detail), which can also be part of the filter module 3.

[0062] To clean the filter 26 in the filter unit 2 and to remove the filter cake that settles on the filter wall 27 during the filtration of the process gas 7, the filter unit 2 must be put into regeneration mode. For this purpose, the filter unit 2 can, as described above, first be removed from the flow of process gas or isolated from the lines by closing the shut-off valves 37 and 38 and thus closing the medium inlet 15 and the medium outlet 16.

[0063] To prepare for the cleaning process, a vacuum is first created in the filter housing 18 using a separate pump, in particular vacuum pump 41. This evacuates the interior 25 of the filter housing 18, which is sealed off by the airlock valve 51 in reactor section 23 (see schematic diagram in [reference]). Figure 5 - Arrow e).

[0064] The vacuum pump 41, which may preferably also be part of the filter module 3, may, and preferably, be an oil-lubricated vacuum pump, such as that known from DE 10 2015 107 721 A1.

[0065] After reaching a negative pressure of, for example, 500 mbar down to, for example, 1 mbar in the area of ​​the interior 25 (detectable via a pressure sensor), the suction process is stopped via the vacuum pump 41 by the control electronics 29.

[0066] A cleaning medium 45 is introduced via a separate cleaning medium reservoir 43, which can also be part of the filter module 3, towards the filter wall 27 via a cleaning line 44 to clean the filter 26. The introduction of the cleaning medium 45 can be triggered by a preferably electrically actuated control valve 46 (see Figure 6 The control valve 46 can be controlled via the control electronics 39.

[0067] The flushing medium 45 can be introduced via, for example, multiple flushing medium inlets 47 and 48 arranged around the longitudinal axis x in the housing roof 20. According to the illustrations, the flushing medium 45 is introduced into the filter interior 34 via the flushing medium inlets 48 in such a way that it flows through the filter wall 27 in a direction c opposite to the flow direction of the medium 7 in normal filter operation (direction d - see illustrations). Figure 4) permeates the filter wall 27. This results in the rinsing medium 45 penetrating the filter wall 27 from the inner surface 36 towards the outer surface 28.

[0068] Simultaneously or at a later time than the flow described above, the rinsing medium 45 is introduced via the radially outer rinsing medium inlet 47 essentially along the outer surface 28 of the filter wall 27 (direction f) in order to safely remove the filter material 32, which is loosened in particular via the portion of the rinsing medium that passes through the filter wall 27 from the inside to the outside, from the intake area towards the bottom of the housing 21.

[0069] The introduction of the rinsing medium 45 can be achieved solely by suction due to the negative pressure prevailing in the interior 25 of the filter housing 18 relative to the surroundings, but can also be achieved, if necessary, by blowing the rinsing medium 45 into the interior 25. The negative pressure in the interior 25 ensures a favorable flow of the rinsing medium over and through the filter wall 27.

[0070] At the end of the cleaning process, the pressure in the interior 25 of the filter housing 18 is preferably the same as in the connected lines (suction line 10 and suction transfer line 17), so that when the shut-off valves 37 and 38 are opened, which in this example achieves the reintegration of the cleaned filter device into the filtration process, no backflow against the usual flow direction of the process gas 7 takes place.

[0071] The same medium is preferably used as the rinsing medium 45 that is also used as a process gas for removing impurities in the cabin 4 of the metal pressure device 1. Thus, argon and / or nitrogen are preferably used as the rinsing medium 45.

[0072] By re-evacuating, a second cleaning process can be carried out immediately after the first cleaning process, if necessary.

[0073] The space 49 formed in reactor section 23 initially forms a funnel-shaped reaction chamber 54 that narrows towards the filter material collection chamber 24. The filter material 32 collected on the bottom side of the filter housing 18, particularly in the area of ​​channel section 52, can be discharged into this reaction chamber 54 after a controlled release following the opening of the sluice valve 51.

[0074] The valve rod supporting the valve disc 53 and the compression spring 50 acting on the valve are housed in a section of reactor section 23 separate from space 49, which may be accessible from the outside (compare, for example, Figure 7 ).

[0075] A pipe 56, extending through the wall 55 of the reactor section 23 to the outside, can open into the reaction chamber 54. This pipe is preferably connected in a flow-tight manner to a vacuum pump, more preferably to the vacuum pump 41. An end section 57 of the pipe 56, facing the bottom of the reaction chamber 54, preferably extends along the longitudinal axis x, with a downwardly directed opening 58 of this end section 57 extending in its plane preferably in a direction transverse to the longitudinal axis x.

[0076] The reaction chamber 54 is preferably designed as a double-walled funnel, with a funnel wall 59 radially outer with respect to the longitudinal axis x and a funnel wall 60 radially inner, so that the reaction chamber 54 is funnel-shaped and ring-shaped around the longitudinal axis x.

[0077] The radially inner upper funnel wall 60, viewed in the axial direction with the filter device 2 in its usual orientation, has an opening 61 in its corrugated area. The end section 57 of the pipe 56 terminates with the opening 58, with an axial distance above the opening 61 in the funnel wall 60 that corresponds to approximately 1 to 2 times the inner diameter of the pipe 56.

[0078] Preferably, the lock valve 51 is also connected to the vacuum pump 41 via a line 62.

[0079] To discharge the filter material 32 collected at the bottom of the filter housing 18 into chamber 49 or the reaction chamber 54 of reactor section 23, a vacuum is created in the reaction chamber 54, and furthermore in the entire chamber 49, which is sealed off from the filter housing 18 by the closed airlock valve 51, via the vacuum pump 41 and the pipeline 56. This vacuum can also be used via the line 62 to open the airlock valve 51 against the restoring force of the compression spring 50. The airlock valve 51 is opened only briefly, but for a sufficient duration to draw the filter material 32 out of the filter housing 18 or the channel section 52 into the reaction chamber 54 via the vacuum in reactor section 23. The filter material 32 then travels along the radially inner surface of the inner funnel wall 60 into the corrugated area and passes through the opening 61.At the end of this transfer process, the filter material 32 lies at the bottom of the funnel-shaped ring-shaped reaction chamber 54 (compare . Figure 8 ).

[0080] Any slight overpressure in the filter housing 18 at the moment the lock valve 51 opens reliably prevents air from entering from room 49 of reactor section 23.

[0081] As soon as the sluice valve 51 is closed again, the pipeline 56 is preferentially opened to the environment. The airflow now entering the vacuum of chamber 49 via the pipeline 56, which acts as a flushing nozzle, is directed through the opening 61 into the reaction chamber 54. This airflow simultaneously causes turbulence of the filter material 32 in the reaction chamber 54 and transports the filter material 32 out of the reaction chamber 54 into the filter material collection chamber 24 (see Figure 5). Figure 9 ).

[0082] In the course of this turbulence and transport, the filter material 32 interacts with the oxygen in the atmospheric air 63 that is drawn in and causes the turbulence, so that, particularly in connection with the turbulence, a passivation of the usually reactive filter material particles is achieved.

[0083] The filter material 32 is blown upwards between the funnel walls 59 and 60 of the reaction chamber 54 by the airflow towards the widening end of the funnel and is brought at its end into a radially outer annular space 64 which substantially surrounds the reaction chamber 54, from which, possibly with further airflow, the filter material 32 enters the filter material collection chamber 24.

[0084] In the filter material collection chamber 24, which is located under atmospheric conditions, the passivated filter material 32 can safely re-react under atmospheric oxygen until the next cleaning cycle.

[0085] According to a preferred embodiment, reactor section 23 can be manufactured largely without support structures despite the given complexity of the interior, for example by 3D metal printing.

[0086] A double-walled outer contour is also preferable. This can be used, for example, for active cooling, such as water cooling.

[0087] The overall tubular free end of the section of reactor section 23 forming the annular space 64 can, preferably, be designed to provide a flow-tight seal for a socket section 65 of the filter material collection chamber 24. The chamber opening 66 surrounding the socket section 65 is preferably closable by means of a shut-off valve 67. A valve cone 68 directed towards the reactor section 23 can be supported in the docking position of the collection chamber 24 against the reactor section 23 by a retainer 69, which in the illustrated embodiment is formed by the downward-facing surface of the outer funnel walls 59 in the corrugated area.

[0088] The shut-off valve 67 is accordingly held in a position releasing the chamber opening 66 (compare Figure 9 ).

[0089] During the passivation process of the separated filter material 32 (schematically represented in the Figures 8 to 10) the filter device 2 can be used as described above to filter the medium 7 passed through the metal pressure device 1.

[0090] After a predetermined number of cleaning cycles, the filter material collection chamber 24 is removed from the filter unit 2 and the contents (collected passivated filter material 32) are disposed of.

[0091] The collection chamber 24 can have rod-like handling elements 70 on its outer wall, for example in the area of ​​the socket section 65, oriented transversely to the longitudinal axis x. These handling elements 70 can be used to transport the collection chamber 24 manually or by means of a transport device 71. In addition, a section of the handling elements 70 can be designed as a sliding handle 82 transversely to the longitudinal axis x, for acting on a slide 81 that serves to lock the filter material collection chamber 24 to the reactor section 23. By pulling the handle 82 radially outwards – with respect to the longitudinal axis x – the locking mechanism can be released.

[0092] According to the Figures 14 to 19 Transport of the collection chamber 24 taken from the filter device 2 using a forklift-like driving device 71 is preferred.

[0093] The transport device 71 preferably has a ground-level chassis 72 with wheels 73. A lifting mast 74 is mounted on the chassis 72 in a substantially vertical orientation, and substantially horizontally oriented fork tines 75 are arranged along this mast and are vertically displaceable, for example, via a lifting chain. The fork tines 75 are designed for the secure gripping of the collection chamber 24, in particular its handling parts 70. For example, a clamping or locking mechanism may be provided when the handling parts 70 are gripped.

[0094] As can be seen, the transport device 71 detects the collection chamber 24 in the area of ​​the handling parts 70, as shown in Figure 14. This detection allows any locking mechanism of the collection chamber 24 on the reactor section 23 to be released, so that the collection chamber 24 can then be transported by means of the transport device 71.

[0095] During the removal of the filter material collection chamber 24 from the reactor section 23, the valve cone 68 loses its support on the retainer 69, as a result of which the shut-off valve 67 automatically falls into a position closing the chamber opening 66 under the influence of a compression spring 76.

[0096] The fork tines 75, together with the collecting chamber 24, are then pivoted about a geometric pivot axis y directed transversely to the vertical extension of the lifting mast 74, preferably by 180°, so that the chamber opening 66 of the collecting chamber 24 points downwards (compare Figure 15 ).

[0097] In this pivoted position, the captured collection chamber 24 can, if necessary, be lifted vertically upwards along the lifting mast 74 in the direction of arrow h (see Figure 16 ), before the feed from the collection chamber 24 to a disposal container 79 according to Figure 17 This has been done.

[0098] The disposal container 79 is provided in the area of ​​its filling opening (not shown in detail) with a pipe-like adapter section 80, which is preferably designed for sealing interaction with the socket section 65 of the collection chamber 24. Preferably, this should enable a tight connection, as is essentially the case between the collection chamber 24 and the reactor section 23.

[0099] This adapter section 80 is connected according to the schematic diagram in Figure 18 By appropriately bringing the collection chamber 24 forward using the transport device 71, the collection chamber 24 is docked, so that the filter material 32 received in the collection chamber 24 can preferably be transferred via the chamber opening 66 into the disposal container 79 solely by gravity.

[0100] The emptied collection chamber 24 is then transported back to the filter unit 2 by means of the transport device 71 and docked there again to the reactor section 23, without any further after-treatment of the collection chamber 24 being necessary (compare Figure 20 ).

[0101] Insofar as reference is made above to process gas, if the filter device is used in connection with a different medium to be cleaned, i.e., in particular, if used in a context other than with a metal pressure device, the process gas may be a different medium. List of reference symbols 1 Metal printing device 29 Guide wall 2 Filter system 30 Front surface 3 Filter module 31 Inlet opening 4 cabin 32 Filtered material 5 laser device 33 outlet opening 6 Tür 34 Filter interior 7 medium 35 annular space 8 Circulating fan 36 Inner surface 9 Pressure line 37 shut-off valve 10 Suction line 38 shut-off valve 11 Medium cooler 39 Control electronics 12 Pre-separator 40 - 13 Fine filter 41 vacuum pump 14 Housing 42 - 15 Media inlet 43 Flushing medium reservoir 16 Medium outlet 44 Flushing line 17 Suction transfer line 45 Flushing medium 18 Filter housing 46 Control valve 19 Housing wall 47 Flushing medium inlet 20 Ceiling 48 Flushing medium inlet 21 Case bottom 49 Space 22 floor opening 50 Compression spring 23 reactor section 51 Lock valve 24 Filter material collection chamber 52 Canal section 25 interior 53 Valve plate 26 filter 54 reaction chamber 27 Filter wall 55 wall 28 Outdoor area 56 Pipeline 57 Final section a Direction 58 opening b Direction 59 funnel wall c Direction 60 funnel wall d Direction 61 opening e Arrow 62 Line f Direction 63 Atmospheric air g Transition direction 64 annular space h Arrow 65 socket section x Longitudinal axis 66 Chamber opening y Swivel axis 67 shut-off valve 68 Valve cone 69 hold-down device 70 Handling part 71 Vehicle 72 chassis 73 wheel 74 mast 75 fork tines 76 Compression spring 77 inlet 78 inlet 79 Disposal container 80 Adapter section 81 Slider 82 handling

Claims

1. Method for cleaning a filter (26) in a filter device (2) having a filter housing (18) and the filter (26) arranged therein, the filter device (2) having a removable filter-material collecting chamber (24), into which filter material (32) accumulating in the course of cleaning the filter (26) is transferred, wherein, upstream of the filter-material collecting chamber (24) in a transfer direction (g) of the filter material (32), a separable space (49) is provided in which the cleaned filter material (32) is treated, with regard to reducing still existing reactivity, by way of passivation, by introducing oxygen, wherein the oxygen is blown into the space (49) or alternatively is drawn into the space (49) as a result of an appropriate application of negative pressure, wherein a swirling of the filter material (32) is carried out in the space (49) and the swirling is carried out simultaneously with the treatment of the filter material (32), and wherein introduced atmospheric air is used both for passivation of the filter material and for transport into the collecting chamber by blowing the filter material out of the reactor space.

2. Method according to claim 1, characterized in that, for discharging filter material (32) collected at the bottom side of the filter housing (18) into the space (49), a negative pressure is generated in the reaction chamber (54) via a vacuum pump (41) and a pipe line (56).

3. Filter device (2) having a filter housing (18) and a filter (26) arranged therein, the filter device (2) having a removable filter-material collecting chamber (24), into which filter material (32) accumulating in the course of cleaning the filter (26) is transferable, wherein, upstream of the filter-material collecting chamber (24) in a transfer direction (g) of the filter material (32), a separable space (49) is provided for treating the cleaned filter material (32) with regard to reducing still existing reactivity, by way of passivation, wherein furthermore, after a cleaning cycle, the filter-material collecting chamber (24) is removable from the filter device (2) in order to feed the contents to a disposal system, and wherein atmospheric air can be introduced into the space (49), atmospheric air allowing, in addition to passivation, both swirling and also transfer of the filter material into the filter-material collecting chamber (24).

4. Filter device (2) according to claim 3,characterized in that the space (49) formed in a reactor section (23) forms a funnel-shaped reaction chamber (54) which narrows in the direction of the filter-material collecting chamber (24), and in that the collected filter material (32) can be discharged into the reaction chamber (54) after controlled release as a result of opening of a lock valve (51).

5. Filter device (2) according to claim 4, characterized in that a pipe line (56) which is guided through the wall of the reactor section (23) to the outside opens into the reaction chamber (54), said pipe line (56) being connected in a fluid-tight manner to a vacuum pump.