Filter device and method for operating a filter device

Abstract

The invention relates to a filter device for separating particles from a particle-containing raw gas stream, the filter device comprising the following: at least one filter module; a filter-module reservoir, associated with the filter module, for receiving filter aid; and an agitation device for agitating filter aid received in the filter-module reservoir, the filter device exhibiting reduced compressed-air consumption and / or reduced energy consumption during agitation operations. According to the invention, the filter device comprises a control device by means of which at least one operating parameter of the agitation device can be varied depending on: a filter-aid demand associated with the at least one filter module; a filter-aid loading (M) associated with the at least one filter module; and / or a target agitation rate (r) associated with the at least one filter module.

Description

[0001] Filter device and method for operating a filter device

[0002] The present invention relates to a filter device for separating particles from a raw gas stream containing particles, wherein the filter device comprises: at least one filter module; a filter module reservoir associated with the filter module for receiving a filter aid; and a swirling device for swirling up filter aid received in the filter module reservoir.

[0003] Such a device is known, for example, from WO 2010 / 069407 Al.

[0004] Using the filter device known from the aforementioned publication, paint overspray is separated from the exhaust air of a paint booth.

[0005] A filter aid, preferably in the form of particles, is used as an aid for filtration in the filter device.

[0006] A commonly used filter aid is rock flour.

[0007] The filter aid is present in a feed container, in which the filter aid is preferably kept in motion and loosened by a mixing device.

[0008] Compressed air, introduced into the feed hopper, agitates the filter aid. This aid is then carried along by the raw gas, laden with particles to be separated, as it enters a filter module and transported to the filter elements of the module. Instead of compressed air, the filter aid can also be agitated using a mixing device in the form of a paddle mixer, where the agitation rate can be adjusted by changing the rotational speed of the mixing tools.

[0009] Filtration at the filter elements of a filter module is carried out as surface filtration on the filter surfaces of the filter elements, which have a high filter class, preferably dust class M.

[0010] The air, which has not been cleaned by the overspray, passes through the filter elements into a clean gas chamber of the filter module.

[0011] A bag filter can be installed as a safety filter in this clean gas room.

[0012] If the filter elements are not installed correctly, for example by applying insufficient torque when tightening the mounting screws, or if a filter element is damaged, filter aid can pass from the raw gas chamber of a filter module into the clean gas chamber of the filter module. In the clean gas chamber of the filter module, the filter aid that has entered is captured by the safety filter.

[0013] The safety filter is monitored for its differential pressure. If the differential pressure rises above a threshold, a warning message is issued indicating that filter aid is present in the safety filter and that the filter module must be checked for leaks.

[0014] A typical, well-known filter system used to remove paint overspray from the spray booths of a vehicle body paint shop comprises filter modules assigned to spray booths that apply different types of paint in several, for example, six, painting phases. For instance, a filler might be applied in two different filler painting phases ("Filler 1" and "Filler 2"), a primer in two different base coat painting phases ("Base Coat 1" and "Base Coat 2"), and a clear coat in two different clear coat painting phases ("Clear Coat 1" and "Clear Coat 2"). All spray booths assigned to the same painting phase are collectively referred to as a production zone. Each production zone of spray booths is assigned a production zone of filter modules, each serving to separate paint particles from that specific production zone.

[0015] Several production zones, in which different types of coatings are applied, can be arranged serially to form a production line. Such a production line could, for example, include a filler production zone, a primer production zone, and a clear coat production zone.

[0016] Alternatively, a production zone may include one or more paint booths in which several painting phases, each using different types of paint, are carried out sequentially. In particular, it may be possible for a production zone to include one or more paint booths in which all painting phases are carried out sequentially.

[0017] Each production zone of filter modules comprises up to 80 filter modules, which are divided, for example, into eight compressed air zones of 10 filter modules each. The control and monitoring of these up to 80 filter modules is carried out via control software that includes a higher-level management module.

[0018] If the filter aid is agitated in the filter module reservoirs by pulses of compressed air, these agitation processes are repeated at fixed time intervals, for example, 10 seconds. In each compressed air zone, only one agitation process can occur in a single filter module reservoir at a time. These agitation processes are triggered by the management module in the control software.

[0019] If the resuspension rate, i.e., the weight of the filter aid that is carried from the filter module reservoir to the filter elements of the filter module and adheres there during a resuspension process of a predetermined length, no longer reaches a predetermined threshold value, then the mixture of filter aid and cleaned particles present in the filter module reservoir must be disposed of and replaced with fresh filter aid.

[0020] In order to dispose of the material from the filter module reservoirs, each production zone in the known filter device is assigned a disposal line, which includes a disposal line and a disposal unit.

[0021] Likewise, each production zone is assigned its own supply line, which includes a supply line and a supply unit.

[0022] The disadvantage of the known filter device described above is that the cyclical stirring up of the filter aid by means of compressed air pulses at fixed time intervals results in a high consumption of compressed air.

[0023] If the filter aid is stirred up using a paddle mixer that is continuously operated at the same rotational frequency, this also results in high energy consumption.

[0024] The present invention is based on the objective of providing a filter device of the type mentioned at the outset, which has a lower compressed air consumption and / or a lower energy consumption for the agitation processes. This objective is achieved in a filter device with the features of the preamble of claim 1 according to the invention in that the filter device comprises a control device by means of which at least one parameter of the operation of the agitation device can be changed as a function of a filter aid requirement associated with the at least one filter module, a filter aid loading M associated with the at least one filter module, and / or a target agitation rate r associated with the at least one filter module.

[0025] The filter aid requirement depends on the concentration of particles to be separated in the raw gas stream fed to a filter module. This filter aid requirement can be characterized by a load factor f, which is explained in more detail below and can, for example, range from 0.5 to 1.0, with a larger factor f corresponding to a greater filter aid requirement.

[0026] The filter aid loading M of a filter module corresponds to the amount of filter aid that has cumulatively migrated from the filter module reservoir assigned to the filter module to the filter elements of the filter element since the last cleaning process and adheres there. The target resuspension rate r can generally be reduced if the existing filter aid loading M is higher.

[0027] The agitation device for agitating filter aid received in the filter module reservoir can comprise one or more of the following devices: one or more agitation nozzles; a mixing device, preferably in the form of a paddle mixer; and / or a fluid floor for fluidizing the contents of the filter module reservoir.

[0028] The swirling device may in particular comprise the following combinations of devices: a fluid floor and one or more swirling nozzles; a paddle mixer and one or more swirling nozzles; and / or a paddle mixer and no swirling nozzles.

[0029] In a preferred embodiment of the invention, at least one of the at least one variable parameter by means of the control device is a cycle time within which a swirling process is repeated, or a swirling duration during which a swirling process is carried out.

[0030] The control device of the filter device is a programmable computer or a system of programmable computers on which a control program of the filter device runs.

[0031] The control device may comprise a central control unit and / or decentralized control units, each assigned to a specific filter module. In this description and in the accompanying claims, the term "control device" is therefore to be interpreted as encompassing both a central control unit and a plurality of decentralized control units, or a combination of a central control unit and several decentralized control units. If a mixing device is assigned to a filter module reservoir of a filter module as a stirring device, it may be provided that at least one of the at least one parameter that can be changed by means of the control device is a rotational frequency of a mixing tool of such a mixing device.

[0032] Preferably, the target stirring rate r is reduced as the filter aid requirement decreases.

[0033] Alternatively or additionally, it may be provided that the target stirring rate r is reduced with increasing filter aid loading M.

[0034] Another disadvantage of the known filter device described above is that providing a separate disposal line and disposal unit, as well as a separate supply line and supply unit, for each production zone is oversized and results in high investment costs. The numerous disposal and supply units are typically operated in standby mode for too long instead of emptying or filling the filter module reservoirs.

[0035] It is therefore advantageous if the filter device according to the invention comprises several filter modules, each filter module being provided for the separation of one of several particle types, the filter device comprising a filter aid disposal system which includes several disposal units, each disposal unit being connected to each of the filter module reservoirs assigned to the filter modules, the fluid connections between the filter module reservoirs and the disposal units being switchable by means of the control device so that several disposal units are simultaneously in fluid connection with each of the filter module reservoirs, the filter modules assigned to these filter module reservoirs being assigned to different production zones and optionally being provided for the separation of different particle types.

[0036] Because, in this embodiment of the filter device according to the invention, the material from each of the filter module reservoirs can be disposed of by means of each of the several disposal units, the number of disposal units required can be reduced and, in particular, be smaller than the number of production zones.

[0037] Furthermore, the fluid connections between the filter module reservoirs and the disposal units are always switched by means of the control device in such a way that only filter module reservoirs that are assigned to different production zones are emptied simultaneously.

[0038] In a preferred embodiment of a filter device according to the invention, it is provided that each disposal unit is assigned a FIFO ("First In, First Out") list, wherein a filter module reservoir to be emptied is entered in the same FIFO list as an already entered filter module reservoir which is assigned to a filter module that is assigned to the same production zone and preferably intended for the separation of the same type of particle as the filter module which is assigned to the newly entered filter module reservoir, if such a filter module reservoir is present in one of the FIFO lists of the disposal units, and otherwise the filter module reservoir to be emptied is entered in the shortest of all FIFO lists of the disposal units.

[0039] This ensures that all disposal processes can be carried out at the filter module reservoirs without emptying two filter module reservoirs assigned to the same production zone simultaneously. Furthermore, by entering the disposal unit into the shortest FIFO list, it is guaranteed that all disposal processes can be completed as quickly as possible.

[0040] Alternatively or additionally to the above-described configuration of the filter aid disposal system, the filter device may comprise several filter modules, each of which is assigned to a production zone and optionally designed to separate one of several particle types, the filter device comprising a filter aid supply system which includes several supply units, each supply unit being connected to each of the filter module reservoirs assigned to the filter modules, the fluid connections between the filter module reservoirs and the supply units being switchable by means of the control device so that several supply units are simultaneously in fluid contact with one of the filter module reservoirs each.The filter modules assigned to these filter module reservoirs are allocated to different production zones and are optionally designed for the separation of different particle types.

[0041] Because, in this embodiment of the filter device according to the invention, each of the filter module reservoirs can be filled with filter aid from each of the supply units, it is achieved that the number of supply units can be reduced and, in particular, can be smaller than the number of production zones.

[0042] The fluid connections between the filter module reservoirs and the supply units are always switched by means of the control device in such a way that only filter module reservoirs that are assigned to different production zones are supplied with filter aid at the same time.In a preferred embodiment of such a filter device, it is provided that each supply unit is assigned a FIFO ("First In, First Out") list, wherein a filter module reservoir to be filled is entered into the same FIFO list as a previously entered filter module reservoir, which is assigned to a filter module that is assigned to the same production zone and preferably intended for the separation of the same type of particle as the filter module which is assigned to the newly entered filter module reservoir, if such a filter module reservoir is present in one of the FIFO lists of the supply units, and otherwise the filter module reservoir to be filled is entered into the shortest of all FIFO lists of the supply units.

[0043] This ensures that at no time are two filter module reservoirs assigned to the same production zone filled with filter aid simultaneously.

[0044] Furthermore, by entering the filter module reservoirs to be filled into the shortest FIFO list of the supply units, it is ensured that all supply processes can be completed in the shortest possible time.

[0045] To reliably determine when the mixture of filter aid and removed particles collected in a filter module reservoir needs to be disposed of and replaced with fresh filter aid, it is advantageous for at least one filter module to be equipped with a cleaning device for removing the mixture of filter aid and separated particles from the filter module. This filter device further includes a monitoring device for monitoring the quantity of filter aid removed during a cleaning process carried out by the cleaning device and for generating a fault message if the removed quantity of filter aid falls below a target cleaning value once or several times. It is particularly advantageous if the target cleaning value is determined based on the quantity of filter aid applied to the filter module before the cleaning process.

[0046] In particular, it may be provided that the cleaning target value is chosen to be higher if the quantity of filter aid arranged in the filter module before the cleaning process is greater.

[0047] For example, the cleaning target value can be chosen proportionally to the amount of filter aid applied to the filter module before the cleaning process.

[0048] The monitoring device may include a container scale by means of which a change in the weight of the material taken up in a filter module reservoir can be determined.

[0049] Using the filter aid disposal system described above and / or the filter aid supply system described above, material exchange is carried out at a filter module reservoir as needed.

[0050] Material replacement at a filter module reservoir preferably takes place when the material contained in the filter module reservoir, a mixture of filter aid and separated particles, can no longer be sufficiently stirred up.

[0051] If, during a dust extraction process, the cleaning target value is undershot and / or a predetermined dust extraction rate r is not reached, a material exchange counter for the relevant filter module reservoir is preferably incremented by 1. When this material exchange counter reaches a set threshold, the material exchange is carried out at the relevant filter module reservoir. Alternatively or additionally, it can also be provided that the material exchange at a filter module reservoir occurs when the production zone of the coating system, to which the filter modules assigned to the relevant filter module reservoir are located, has been traversed by a predetermined number of workpieces, for example, vehicle bodies.This ensures that a material exchange at a filter module reservoir takes place at the latest when the specified number of workpieces that have passed through the relevant production zone has been reached.

[0052] Instead of a predetermined number of workpieces, a predetermined number of workpiece carriers, for example skid frames, can also be defined, whereby a material exchange then takes place at a filter module reservoir when the predetermined number of workpiece carriers that have passed through the production zone in question has been reached.

[0053] Preferably, whenever a workpiece has passed through the relevant production zone, a workpiece counter for the corresponding filter module reservoir is incremented by 1. When this workpiece counter reaches a preset threshold, the material exchange at the relevant filter module reservoir is carried out.

[0054] Alternatively or additionally, it can also be provided that when a workpiece carrier, for example a skid frame, has passed through the relevant production zone, a workpiece carrier counter for the corresponding filter module reservoir is incremented by 1. When this workpiece carrier counter reaches a preset threshold, the material exchange at the relevant filter module reservoir is carried out. It can happen that the material contained in a filter module reservoir, a mixture of filter aid and separated particles, is difficult to disperse, either immediately after refilling with new filter aid or only for a short time after refilling.In such a case, the material exchange counter reaches the set threshold value after a very short time, which would actually trigger a material exchange at the relevant filter module reservoir, even though such a material exchange is not yet necessary.

[0055] To prevent such unnecessary material exchange, it can be provided that the material exchange at a filter module reservoir is only carried out if not only the material exchange counter has reached the set threshold value, but also the workpiece counter and / or the workpiece carrier counter for the filter module reservoir in question has reached a predetermined minimum value.

[0056] This specified minimum value can correspond to a certain fraction of the number of workpieces or workpiece carriers, at the latest when a material exchange is carried out.

[0057] For example, it can be stipulated that the minimum value of the workpiece counter or the workpiece carrier counter required for carrying out a material exchange at a filter module reservoir corresponds to at least one-sixth, in particular at least one-third, and most preferably at least half, of the number of workpieces or the number of workpiece carriers at which a material exchange is carried out at the filter module reservoir in question. Introducing these additional conditions for the material exchange prevents unnecessary material exchange from being carried out in filter module reservoirs whose contents are difficult to agitate, even shortly after refilling with fresh filter aid.

[0058] Another disadvantage of the filter device described at the beginning, according to the state of the art, is that the bag filters used as safety filters on the clean gas side of the filter modules are continuously permeated by the purified gas flow, resulting in a pressure loss and thus unnecessary energy consumption.

[0059] In a particular embodiment of the filter device according to the invention, it is therefore provided that the filter device comprises at least one dust sensor which is arranged in the flow path of the gas cleaned of particles downstream of a filter module, wherein a leakage counter of the filter module is incremented by the control device when a dust quantity exceeding a threshold value is detected by means of the dust sensor and the filter module in question is being cleaned of a mixture of filter aid and separated particles during the time of detection or when the filter module in question was the last filter module that was cleaned of a mixture of filter aid and separated particles before the time of detection.

[0060] In this way, it is possible to reliably detect smaller leaks of filter aid to the clean gas side of the filter modules using one or more dust sensors, so that leaks occurring during the operation of the filter device can be rectified quickly and reliably.

[0061] In this case, it is particularly advantageous if no safety filters, especially no bag filters, are arranged on the clean gas side of the filter modules. It is also particularly advantageous if the leakage counter of the filter module is decremented by the control device when a cleaning process has been carried out on the filter module and no dust concentration exceeding the threshold value has been detected by the at least one dust sensor during the cleaning process and within a specified grace period after the cleaning process.

[0062] In this way, erroneous assignments of leakage events to a filter module can be corrected, especially if a filter module has been cleaned at the same time as another, defective filter module.

[0063] Another disadvantage of the state-of-the-art filter device described above is that the filter aid is stirred up in the filter module reservoirs even when no raw gas stream laden with particles to be separated reaches the filter modules for an extended period. This leads to unnecessarily high energy consumption.

[0064] In a preferred embodiment of the invention, it is therefore provided that a filter module of the filter device can be switched to a sleep mode by the control device if the filter module in question is not cleaned and is covered with a predetermined minimum amount of the filter aid, and if the filter module reservoir associated with the filter module is neither emptied nor filled with filter aid, and if no treatment process that increases the particle concentration in the raw gas stream is carried out on a workpiece, in particular on a vehicle body, within a predetermined pause time.

[0065] It is preferably provided that when a filter module is in sleep mode, the associated agitation device and / or cleaning device are not activated. This results in significant energy savings when longer treatment breaks occur during the processing of workpieces in the treatment system associated with the filter device, particularly a coating system, such as a paint shop.

[0066] It is particularly advantageous if all filter modules of the filter device can be switched to a sleep mode by the control device under the aforementioned conditions.

[0067] Optionally, it can also be provided that, under the aforementioned conditions, the exhaust fan of the filter device can be switched by the control device into a sleep mode in which the volume flow through the exhaust fan is preferably reduced.

[0068] The filter device according to the invention may preferably have one or more of the following advantages compared to known filter devices according to the prior art:

[0069] Achieving energy savings over the entire operating time of the filter device through a lower pressure loss when passing through the filter modules.

[0070] Faster detection of leaks where filter aid gets onto the clean gas side of a filter module.

[0071] Lower consumption of filter aid.

[0072] Lower investment costs for the manufacture of the filter device due to the elimination of the compressed air sections to which the filter modules are assigned in filter devices according to the state of the art. Lower investment costs for the manufacture of the filter aid disposal system and the filter aid supply system because fewer disposal units and supply units, respectively, are required.

[0073] In particular, the number of supply units can be smaller than the number of production zones to which the filter modules of the filter device are assigned, and preferably no more than three.

[0074] Similarly, the number of disposal units can be less than the number of production zones to which the filter modules of the filter device are assigned, and preferably no more than three.

[0075] The present invention further relates to a method for operating a filter device for separating particles from a raw gas stream containing particles, wherein the filter device comprises at least one filter module, a filter module reservoir associated with the filter module for receiving a filter aid and a swirling device for swirling up filter aid received at the filter module reservoir.

[0076] The present invention is based on the further objective of creating a method for operating a filter device in which the energy requirement and / or the requirement for compressed air for the operation of the filter device is reduced.

[0077] This problem is solved in a method according to the preamble of claim 16 according to the invention by means of a control device of the filter device in that at least one parameter of the operation of the swirling device is changed as a function of a filter aid requirement assigned to the at least one filter module, a filter aid loading M assigned to the at least one filter module and / or a Sol I swirling rate r assigned to the at least one filter module.By adapting at least one parameter of the operation of the agitation device to the actual filter aid requirement of a filter module, the actual filter aid occupancy M of a filter module and / or a target agitation rate r actually required by a filter module, the unnecessary execution of agitation processes, an unnecessarily short interval between two agitation processes, an unnecessarily long duration of agitation processes and / or, especially when using a paddle mixer as part of the agitation device, an unnecessarily high rotational frequency of the paddle mixer can be prevented, thereby achieving a considerable saving of energy and / or compressed air.

[0078] The inventive method for operating a filter device is preferably carried out using a computer.

[0079] The inventive method for operating a filter device is particularly suitable for operating the inventive filter device for separating particles from a raw gas stream containing particles.

[0080] The filter device according to the invention for separating particles from a raw gas stream containing particles is preferably operated according to the method according to the invention for operating such a filter device.

[0081] Specific embodiments of the inventive method for operating a filter device for separating particles from a particle-containing raw gas stream have already been explained above in connection with specific embodiments of the inventive filter device for separating particles from a particle-containing raw gas stream; this information relating to the inventive filter device can be transferred analogously to the inventive method for operating a filter device for separating particles from a particle-containing raw gas stream.

[0082] Further features and advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

[0083] The drawings show:

[0084] Fig. 1 shows a schematic vertical cross-section through a filter module of a filter device used to separate particles from a raw gas stream containing particles, wherein the raw gas stream originates from at least one paint booth of a paint shop, and a schematic representation of an exhaust air duct with a blower arranged downstream of the filter module;

[0085] Fig. 2 shows a schematic representation of the filter module reservoirs assigned to the filter modules of the filter device, which serve to hold a filter aid, wherein the filter modules assigned to the filter module reservoirs are assigned to different production zones and the filter module reservoirs assigned to the same production zone are each connected to a common supply line;

[0086] Fig. 3 shows a schematic representation of several supply units of a filter aid supply system of the filter device, wherein each of the supply units is connected to each of the filter module reservoirs assigned to the filter modules; Fig. 4 shows a schematic representation of the filter module reservoirs of the filter device, wherein each filter module reservoir is assigned to a filter module and the filter modules are assigned to different production zones, wherein the filter module reservoirs which are assigned to the same production zone are each connected to a common disposal line;

[0087] Fig. 5 shows a schematic representation of several disposal units of a filter aid disposal system of the filter device, wherein each of the disposal units is connected to each of the filter module reservoirs of the filter device;

[0088] Fig. 6 shows a diagram showing the target resuspension rate r (in kg) to be maintained as a function of the filter aid loading M (in kilograms) of a filter module, wherein the target resuspension rate r depends on a load factor f of the respective module, which is assigned to the filter modules depending on the load of the respective filter module with particles to be separated from the raw gas stream;

[0089] Fig. 7 shows a flow diagram illustrating the operational control of a swirling process at a filter module, wherein a swirling device of the filter module comprises swirling nozzles for swirling filter aid from a filter module reservoir associated with the filter module;

[0090] Fig. 8 shows a schematic vertical section through several filter modules and a filter module reservoir associated with the several filter modules, wherein the filter module reservoir is provided with a mixing device for stirring up filter aid contained in the filter module reservoir and the mixing device comprises a paddle mixer; Fig. 9 shows a flow diagram illustrating the operational control of a stirring process at a filter module to which a filter module reservoir is associated, which is provided with a mixing device comprising a paddle mixer for stirring up filter aid contained in the filter module reservoir;

[0091] Fig. 10 shows a flowchart illustrating the operational control of a filter aid supply process at a filter module reservoir of the filter device;

[0092] Fig. 11 shows a flowchart illustrating the operational control of a filter aid disposal process at a filter module reservoir of the filter device;

[0093] Fig. 12 is a flowchart illustrating the operational control of switching a filter module of the filter device into a sleep mode;

[0094] Fig. 13 shows a schematic vertical cross-section through an alternative embodiment of a filter module and a filter module reservoir associated with the filter module, wherein the filter module reservoir is associated with only a single filter module, the filter module reservoir is provided with a mixing device for stirring up filter aid contained in the filter module reservoir, and the mixing device comprises a paddle mixer; and

[0095] Fig. 14 shows a top view of the filter module reservoir from Fig. 13, including the paddle mixer and a rotary drive for the paddle mixer. Identical or functionally equivalent elements are designated with the same reference numerals in all figures.

[0096] A filter device, shown in partial detail in Figs. 1 to 5 and designated as a whole by 100, for separating particles from a raw gas stream containing particles comprises a plurality of filter modules 102, one of which is shown schematically in a vertical cross-section in Fig. 1.

[0097] The filter device 100 serves, for example, to separate particles from a particle-containing raw gas stream, which is supplied to the filter device 100 from one or more paint booths of a (not shown) system for spray painting vehicle bodies.

[0098] In this process, the vehicle bodies are moved along a conveying direction through application areas of the paint booths by means of a (not shown) conveying device.

[0099] Spray painting equipment, for example in the form of painting robots, is located in the application areas of the paint booths.

[0100] A recirculating air system generates an airflow that essentially passes vertically from top to bottom through the application areas of the paint booths.

[0101] This airflow does not pick up paint overspray in the application areas in the form of overspray particles. In this description and in the attached claims, the term "particle" includes both solid and liquid particles, in particular droplets.

[0102] When using fluid lacquer, the fluid lacquer overspray consists of lacquer droplets. Most of the overspray particles have a maximum dimension in the range of 1 pm to approximately 100 pm. The exhaust air stream loaded with overspray particles from the application areas is referred to below as the raw gas stream. The flow direction of the raw gas stream is shown in Fig. 1 by arrows 120.

[0103] The raw gas stream leaves the paint booth downwards and enters the filter device 100, which is preferably located at least partially below the application areas.

[0104] Each of the filter modules 102 is preferably designed as a pre-assembled unit, which is manufactured at a location remote from the assembly location of the filter device 100 and transported as a unit to the assembly location of the filter device 100.

[0105] As can be seen from Fig. 1, the filter module 102 comprises a housing 104, in the interior 105 of which at least one filter element 106, preferably several filter elements 106, is or are arranged.

[0106] The filter elements 106 can, for example, be made of sintered polyethylene plates which are provided on their outer surface with a membrane made of polytetrafluoroethylene (PTFE).

[0107] The PTFE coating serves to increase the filter class of the filter elements 106 (i.e., to reduce their permeability) and also to prevent the permanent adhesion of the fluid lacquer overspray separated from the raw gas stream.

[0108] Both the base material of the filter elements 106 and their PTFE coating exhibit porosity, allowing the raw gas to pass through the pores into the interior of the respective filter element 106. To prevent the surfaces of the filter elements 106 from sticking together, they are further provided with a barrier layer of filter aid released into the raw gas stream. This preferably particulate filter aid is also frequently referred to as "precoaf" material.

[0109] The barrier layer is formed during the operation of a filter module 102 by deposition of the filter aid released into the raw gas stream 120 on the filter surfaces of the filter elements 106 and prevents the filter surfaces from sticking together due to adhering fluid varnish overspray.

[0110] In principle, any medium can be used as a filter aid that is able to absorb the liquid component of the fluid lacquer overspray and adhere to overspray particles, thus removing their stickiness.

[0111] Suitable filter aids include, for example, stone flour, lime, aluminium silicate, aluminium oxide, silicon oxide, powder coating or similar materials.

[0112] Alternatively or additionally, particles with a hollow structure and a relatively large internal surface area compared to their external dimensions can also be used as filter aids to absorb and / or bind the overspray, for example zeolite or other hollow, e.g. spherical bodies made of polymers, glass or aluminum silicate and / or natural or synthetically produced fibers.

[0113] A waste product from a production process can also be used as a filter aid, for example, waste from powder coating processing or wood or metal dust from wood or metal processing. The filter aid preferably consists of a plurality of filter aid particles, which preferably have a mean diameter in the range of, for example, approximately 4 pm to approximately 100 pm, and particularly preferably in the range of approximately 4 pm to approximately 10 pm.

[0114] In order to be able to add the filter aid to the raw gas stream 120 without the risk of the filter aid entering the application areas of the paint booths, each filter module 102 is provided with a filter module reservoir 108, which, for example, has a funnel-shaped form in the shape of an inverted truncated pyramid (see Fig. 1).

[0115] An access opening 110 is formed between an upper edge of the filter module reservoir 108 and a lower edge of the housing 104, through which the raw gas stream 120 loaded with particles can enter and reach filter elements 106.

[0116] A substantially horizontally oriented bottom 112 of the filter module reservoir 108 is designed as a porous fluid bottom 114, which can be flushed with a gaseous medium, in particular with compressed air, in order to fluidize the filter aid arranged in the interior 116 of the filter module reservoir 108 and to equalize locally different fill levels of the filter aid within the filter module reservoir 108.

[0117] A compressed air pipeline 118 is held on a side wall of the filter module reservoir 108, which leads to outlet nozzles 126 of a turbulence device 122.

[0118] The agitation device 122 serves to deliver compressed air pulses into the filter aid located below it in order to agitate this filter aid and thus introduce it into the raw gas stream 120 passing through the filter module 102. Furthermore, the agitation of the filter aid by means of the agitation device 122 homogenizes the mixture of filter aid and the separated particles bound to it present in the filter module reservoir 108.

[0119] In the embodiment of a filter device 100 shown in Fig. 1, the fluid base 114 also belongs to the agitation device 122, since the fluidization of the filter aid in the filter module reservoir 108 facilitates the agitation of the filter aid. In principle, however, the filter module reservoir 108 could also be designed without a fluid base 114.

[0120] During the operation of the filter module 102, the vortexing device 122 is intermittently put into operation, which will be explained in more detail below.

[0121] The swirling device 122 preferably comprises several, for example two, outlet nozzles 126 for compressed air, which are designed, for example, as cone nozzles and can each generate a compressed air cone that widens downwards towards the bottom 112 of the filter module reservoir 108.

[0122] The base 112 of the filter module reservoir 108 rests on a (not shown) container scale, which is supported on a base.

[0123] The sum of the weight of the filter module reservoir 108 and the mixture of filter aid and separated particles contained therein can be measured using the container scale.

[0124] The container scale generates an electrical measuring signal, which is transmitted via a signal line (not shown) to a control device 128 of the filter device 100, schematically depicted in Fig. 1. Since the access opening 110 of the filter module 102 forms a constriction where the raw gas velocity is particularly high, it effectively prevents filter aid from escaping from the filter module reservoir 108 or from the interior 105 of the filter module 102 into the application areas of the paint booths. The filter aid can therefore be stirred up in the filter module reservoir 108 at any time without interrupting the supply of raw gas to the filter module 102 or even the operation of the spray painting equipment in the application areas.

[0125] During operation of the filter module 102, the raw gas stream 120 passes over the filter surfaces of the filter elements 106, whereby both the entrained filter aid and the entrained overspray particles are deposited on the filter surfaces, and the filtered raw gas passes as an exhaust air stream through the porous filter surfaces into the interiors of the filter elements 106, which are connected to a cavity within a base body 130 from which the filter elements 106 protrude. From this cavity, the purified exhaust air stream flows into an exhaust air duct 132, which leads from the base body 130 of the filter elements 106 of the respective filter module 102 to an exhaust air channel 134.

[0126] A dust sensor 135 is arranged in the exhaust duct 134.

[0127] As can be seen in Fig. 1, the exhaust air, cleaned of overspray particles, passes from the exhaust duct 134 to an exhaust fan 136. From there, the cleaned exhaust air is fed via a cooling coil (not shown) and a supply line (not shown) to an air chamber (not shown) located above the application areas, the so-called plenum. From this air chamber, the cleaned exhaust air passes through a filter ceiling back into the application areas of the paint booths. A large portion of the air passing through the application areas is thus circulated in a recirculation loop that includes the application areas, the filter modules 102, the exhaust ducts 132, the exhaust duct 134, the exhaust fan 136, the supply line, and the air chamber above the application areas.

[0128] The filter elements 106 of a filter module 102 are cleaned at specific time intervals, when their loading with overspray particles and filter aid has reached a predetermined level, by means of a cleaning device 143 using compressed air pulses, which will be explained in more detail below.

[0129] The cleaning device 143 comprises a pulse unit 138, which is arranged on the base body 130 of the filter elements 106 of each filter module 102 and by means of which the compressed air pulses required for cleaning the filter elements 106 are generated, wherein the pulse unit 138 is able to deliver pressure pulses via a pulse valve 140 to compressed air pipes or compressed air lances 142, which run within the respective base body 130 and direct the compressed air into the interiors of the filter elements 106.

[0130] The discharge unit 138 includes a compressed air reservoir which empties abruptly when the discharge valve 140 is opened.

[0131] From the interior of the filter elements 106, the compressed air pulses pass through the porous filter surfaces into the interior 105 of the housing 104, thereby removing the barrier layer formed on the filter surfaces of the filter elements 106, consisting of filter aid and the overspray particles deposited thereon, so that the filter surfaces are restored to their original, cleaned state. A refill valve 144 is associated with the pulse unit 138, through which compressed air can be supplied to the pulse unit 138 from a compressed air supply line 146, which is supplied by a compressor 148, to refill the compressed air reservoir of the pulse unit 138.

[0132] The compressed air pipeline 118, which leads to the outlet nozzles 126 of the swirling device 122, is also connected to this compressed air supply line 146 via a compressed air valve 150.

[0133] Furthermore, the fluid base 114 of the filter module reservoir 108 is also connected to the compressed air supply line 146 via a compressed air line 154 equipped with a compressed air valve 152.

[0134] By opening the pulse valve 140, the compressed air valve 150 or the compressed air valve 152, a cleaning of the filter elements 106, a stirring up of the filter aid in the filter module reservoir 108 or a fluidization of the filter aid in the filter module reservoir 108 by means of the fluid floor 114 can be triggered alternately or simultaneously.

[0135] Between the aforementioned compressed air valves and the compressor 148, a shut-off valve 156 is arranged in the compressed air supply line 146, which - like the other valves of the filter device 100 - can be controlled by the control device 128, which is arranged, for example, in a local control room.

[0136] The discharge unit 138 including the compressed air reservoir, as well as the discharge valve 140 and the refill valve 144, can also be arranged outside the base body 130, unlike as shown in Fig. 1.

[0137] The control device 128 shuts off the compressed air supply from the compressor 148 to the aforementioned compressed air consumers of a filter module 102 or all filter modules 102 by closing the shut-off valve 156 if it detects that there is insufficient raw gas flow through the filter elements 106. To determine whether there is sufficient raw gas flow through the filter elements 106, the control device 128 may, for example, monitor the operating status of the exhaust fan 136.

[0138] This monitoring of the operating status of the exhaust fan 136 can be carried out, for example, by means of a differential pressure gauge (PDIA) 158, which measures the pressure drop between the pressure side and the suction side of the exhaust fan 138.

[0139] Alternatively or additionally, the operating status of the exhaust fan 136 can also be monitored by the control device 128 by means of a current monitoring device (ESA) 160 and / or by means of a frequency converter (SC) 162.

[0140] Furthermore, it may be provided that the lack of sufficient raw gas flow through the filter elements 106 is determined by means of a flow meter (FIA) 164, which measures the gas flow through the exhaust duct 134 or through one or more of the exhaust lines 132.

[0141] Furthermore, it is possible to determine the lack of sufficient raw gas flow through the filter elements 106 by measuring the pressure drop at the filter elements 106 of a filter module 102 or all filter modules 102 using a differential pressure gauge (PDIA) 166, which measures the pressure drop between the interior of the respective filter module 102 on the one hand and the interior of the base body 130 on the other.

[0142] If the control device 128 determines, based on the signals transmitted to it by the differential pressure gauge 158, the current monitoring device 160, the frequency converter 162 and / or the flow meter 164, that the raw gas flow through the filter elements 106 is below a predetermined threshold value, the compressed air supply to at least one of the filter modules 102 is blocked by closing the shut-off valve 156.

[0143] In this way, it is prevented that filter aid, by means of the swirling device 122, by cleaning the filter elements 106 or by fluidizing the filter aid supply in the filter module reservoir 108, enters the flow path of the raw gas and, in particular, enters the application areas of the paint booths through the inlet opening 110.

[0144] In the filter device 100 described above, the filter aid is added to the raw gas stream 120 for the separation of particles from the particle-containing raw gas stream 120 exclusively by stirring up the filter aid in the filter module reservoir 108 assigned to each filter module 102.

[0145] In order to supply fresh filter aid to the filter module reservoirs 108, the filter device 100 for separating particles from a particle-containing raw gas stream 120 comprises a filter aid supply system 168 shown schematically in Figs. 2 and 3.

[0146] Fig. 2 shows that the filter modules 102 and the associated filter module reservoirs 108 are each assigned to a group of filter modules 102 or a group 170 of filter module reservoirs 108, wherein each filter module 102 of such a group or each filter module reservoir 108 of such a group 170 is assigned to a production zone and is intended for the separation of one specific of several particle types.

[0147] Thus, the filter module reservoirs 108 of a first group 170a of filter module reservoirs 108 are assigned to filter modules 102 that are intended for the separation of particles of a filler coating in a first "primer" production zone P 1 (first filler coating). A second group 170b of filter module reservoirs 108 comprises filter module reservoirs 108 that are assigned to filter modules 102 that are intended for the separation of particles of a base coat in a first "base coat" production zone BC 1 (first base coat).

[0148] Another group 170c of filter module reservoirs 108 comprises filter module reservoirs 108 which are assigned to filter modules 102 which are intended for the separation of particles of a clear coat in a first "Clear Coat" production zone CC 1 (first clear coat).

[0149] A fourth group 170d of filter module reservoirs 108 comprises filter module reservoirs 108 which are assigned to filter modules 102 which are intended for the separation of particles of a filler lacquer in a second "primer" production zone P 2 (second filler lacquer).

[0150] A fifth group 170e of filter module reservoirs 108 comprises filter module reservoirs 108 which are assigned to filter modules 102 which are intended for the separation of particles of a base coat in a second "Base Coat" production zone BC 2 (second base coat).

[0151] A sixth group 170f of filter module reservoirs 108 comprises filter module reservoirs 108 which are assigned to filter modules 102 which are intended for the separation of particles of a clear coat in a second "Clear Coat" production zone CC 2 (second clear coat).

[0152] Each of the groups 170 of filter module reservoirs 108 comprises n filter module reservoirs 108, which are designated RI to Rn in Fig. 2, where the number n of filter module reservoirs 108 in each group 170 of filter module reservoirs 108 can be different. As can be seen from Fig. 2, each filter module reservoir 108 of a group 170 of filter module reservoirs 108 is connected via a branch line 174 equipped with a pinch valve 172 to a common supply line 176 of the respective group 170 of filter module reservoirs 108. The branch lines 174 can, for example, be tubular.

[0153] In the direction of flow of the filter aid, a further pinch valve 178 is preferably arranged between each of two branches of spur lines 174 from the supply line 176.

[0154] As can be seen from Fig. 3, the filter aid supply system 168 further comprises several supply units 180, three in the embodiment shown in the drawing. Each of the supply units 180a, 180b and 180c comprises a supply silo 182, which contains a supply of filter aid, wherein the supply silo 182 is connected to a filter aid supply line 186 via a rotary valve 184.

[0155] Alternatively, it can also be provided that two or more of the supply units 180a, 180b and 180c, preferably all supply units 180a, 180b and 180c, comprise a common supply silo 182.

[0156] The respective filter aid supply line 186 branches into a number N of filter aid branch lines 188, wherein the number N of filter aid branch lines 188 corresponds to the number N of supply lines 176 of the N groups 170 of filter module reservoirs 108.

[0157] Each of the filter aid branch lines 188 can be blocked or opened by means of a valve 190 and is connected to a corresponding supply line 176. In this way, each of the supply units 180a, 180b and 180c is connected to each of the supply lines 176 and thus to each filter module reservoir 108 of all N groups 170 of filter module reservoirs 108.

[0158] Each of the supply units 180 also includes a supply air line 192 in which a blower 194 is arranged and which branches into an exhaust air line 196 and a conveying line 198.

[0159] The exhaust air duct 196 can be opened or closed by means of a flap 200.

[0160] The conveying line 198 can be opened or closed by means of a flap 202.

[0161] The conveying line 198 is connected to the rotary valve 184 of the respective supply unit 180, so that when the flap 202 is open, filter aid material that has entered the rotary valve 184 can be conveyed by means of the supply air in the conveying line 198 through the filter aid supply line 186 and the respective open filter aid branch line 188 into the supply line 176 assigned to the open filter aid branch line 188.

[0162] From the supply line 176, which is supplied with filter aid, the filter aid then enters the filter module reservoir 108 of the group 170 of filter module reservoirs 108 assigned to this supply line 176, whose pinch valve 172 is open.

[0163] If a supply unit 180 is not to be used for conveying filter aid into one of the filter module reservoirs 108, the supply air from the supply air line 192 is discharged through the open flap 200 of the exhaust air line 196, while the flap 202 of the conveying line 198 remains closed. Furthermore, each of the supply units 180 preferably comprises a compressed air line 204 in which a compressed air valve 206 is arranged for opening or closing the compressed air line 204 and which is connected to the rotary valve 184 of the respective supply unit 180 in order to fluidize filter aid contained in the rotary valve 184 as required and to convey it from the rotary valve 184 into the filter aid supply line 186.

[0164] In order to be able to remove the filter aid accumulated in a filter module reservoir 108, mixed with separated particles, and to dispose of or recycle it before fresh filter aid is supplied to it, the filter device 100 for separating particles from a particle-containing raw gas stream 120 comprises a filter aid disposal system 208 as shown schematically in Figs. 4 and 5.

[0165] Fig. 4 shows the filter module reservoirs 108 assigned to the filter modules 102 of the filter device 100, each of which is assigned to one of the groups 170a to 170f of filter module reservoirs 108, wherein each filter module reservoir 108 is assigned to such a group 170 of a production zone and is provided for the separation of one specific of several particle types.

[0166] Each of the groups 170 of filter module reservoirs 108 comprises n filter module reservoirs 108, which are designated RI to Rn in Fig. 4, where the number n of filter module reservoirs 108 of each group 170 of filter module reservoirs 108 can be different.

[0167] As can be seen in Fig. 4, each filter module reservoir of a group 170 of filter module reservoirs 108 is connected via a branch line 212 equipped with a pinch valve 210 to a common discharge line 214 of the respective group 170 of filter module reservoirs 108. A ball valve 216 can be arranged at the end of each discharge line 214, through which conveying air can be supplied into the respective discharge line 214 as needed to facilitate the extraction of the filter aid from the discharge line 214.

[0168] The branch lines 212 each open just above the fluid floor 114 into the interior 116 of the respective filter module reservoir 108, preferably in a corner area of ​​the filter module reservoir 108, where two side walls of the filter module reservoir 108 meet.

[0169] As can be seen from Fig. 5, the filter aid disposal system 208 further comprises several disposal units 218, three in the embodiment shown in the drawing.

[0170] Each of the disposal units 218a, 218b and 218c includes a collection reservoir 220 in which filter aid drawn from one of the filter module reservoirs 108 via one of the disposal lines 214 can be temporarily stored.

[0171] Each collection reservoir 220 of each disposal unit 218 is fed by a filter aid discharge line 222, which branches upstream into a number N of filter aid branch lines 224, wherein the number N of filter aid branch lines 224 corresponds to the number N of disposal lines 214 of the N groups 170 of filter module reservoirs 108.

[0172] Each of the filter aid branch lines 224 can be blocked or opened by means of a valve 226 and is connected to a corresponding disposal line 214. In this way, each of the disposal units 218a, 218b and 218c is connected to each of the disposal lines 214 and thus to each filter module reservoir 108 of all N groups 170 of filter module reservoirs 108.

[0173] Each of the disposal units 218 also includes an exhaust air duct 228, which is connected to the interior of the collection reservoir 220 of the disposal unit 218 and in which a suction blower 230 is arranged.

[0174] By means of the suction blower 230, a mixture of filter aid and separated particles can be drawn from a filter module reservoir 108, whose pinch valve 210 is open, through the respective associated disposal line 214, an open valve 226 of a filter aid branch line 224 and the filter aid discharge line 222 into the collection reservoir 220 of the disposal unit 218.

[0175] Each of the disposal units 218 further comprises a fluidization nozzle 232 arranged in the interior of the collection reservoir 220, to which compressed air can be supplied via a compressed air line 234, wherein the compressed air line 234 can be opened or closed by means of a compressed air valve 236.

[0176] Furthermore, each of the disposal units 218 includes a slide valve 236, via which the collection reservoir 220 of the disposal unit 218 is connected to a collection container 238 for receiving a mixture of filter aid and separated particles.

[0177] In the embodiment shown in Fig. 5, a common collection container 238 is provided for all disposal units 218. However, it would also be possible, in principle, for each disposal unit 218 to have its own collection container 238. Furthermore, each disposal unit 218 includes a compressed air control line 240, through which compressed air can be supplied to the slide valve 236 in order to switch the slide valve 236 to the open and / or closed position.

[0178] The compressed air control line 240 can be opened or closed by means of a control valve 242 arranged therein.

[0179] The material extracted from the filter module reservoirs 108, which contains filter aid together with separated particles, can either be disposed of or - if necessary after processing - at least partially reused in the filter device 100.

[0180] Furthermore, it may be provided that the composition of the filter aid is selected in such a way that the filter aid mixed with separated particles can be used after use in the filter device 100 for purposes other than for the protection of the filter elements 106 of the filter device 100.

[0181] For example, the used filter aid can be used as insulation material or thermally recycled, for example in the brick industry or cement industry or the like, whereby the paint particles bound to the filter aid can also be used as energy carriers in a combustion process required for production.

[0182] In the filter device 100 described above, the commissioning of the agitation device 122 of a filter module reservoir 108, unlike in the prior art, no longer takes place cyclically with a fixed predetermined period; rather, at least one parameter of the operation of the agitation device 122 is changed by means of the control device 128, on which a control program runs, depending on a filter aid requirement assigned to the respective filter module 102, depending on a filter aid loading M assigned to the filter module 102 and / or depending on a target agitation rate r assigned to the filter module 102.

[0183] The parameter of the operation of the swirling device 122 that can be changed by means of the control device 128 is, for example, a cycle time within which a swirling process carried out by means of the swirling device 122 is repeated.

[0184] The various filter modules 102, to which the filter module reservoirs 108 are assigned, are classified into different load categories according to the filter aid consumption per object to be painted, in particular per vehicle body.

[0185] Heavily loaded filter modules 102 are those filter modules 102 to which a raw gas stream 120 loaded with a particularly high number of particles is supplied. This raw gas stream originates from parts of the application areas where a particularly high amount of paint overspray occurs.

[0186] Low-load filter modules 102 are those filter modules 102 to which a raw gas stream 120 with fewer particles is supplied. Such a less loaded raw gas stream 120 originates from parts of the application areas where less paint overspray occurs.

[0187] To characterize the load on the filter modules 102, a load factor f is defined, whereby the load factor f is a maximum of 1.0 for very heavily loaded filter modules 102 and decreases with decreasing load on the filter modules 102, for example to a value of 0.5. Depending on the current filter aid loading M of a filter module 102 and the load factor f of the filter module 102, a target agitation rate r currently assigned to the filter module 102 is then determined.

[0188] This determination is made using curves which indicate the course of the desired target turbulence rate r as a function of the filter aid loading M of the respective filter module 102, whereby these curves are parameterized by the load factor f.

[0189] Such curves, which define the target stirring rate r (example given in kg) as a function of the filter aid loading M (example also given in kg), are shown in the diagram of Fig. 6 for four different values ​​of the load factor f serving as a parameter, whereby the curves shown in Fig. 6 correspond to the values ​​f = 1.0 (marked by the symbol x), f = 0.9 (marked by the symbol o), f = 0.8 (marked by the symbol □) and f = 0.7 (marked by the symbol A).

[0190] As explained above, heavily loaded filter modules 102 with a high demand for filter aid are assigned a high load factor f, while lightly loaded filter modules with a low demand for filter aid are assigned a lower load factor f.

[0191] The curves in Fig. 6 result from the fact that the target stirring rate r is assigned a constant starting value of 2.5 kg for low filter aid loadings M (for example up to M = 20 kg).

[0192] As soon as more than 20 kg of filter aid is present on the filter elements 106 of a filter module 102, the further course of the target agitation rate r is determined as a function of the filter aid loading M according to the formula r = r start ■ f / K (M / 20kg) calculated.

[0193] The lower the load factor f, the more the target stirring rate r decreases with increasing filter aid loading M.

[0194] The resuspension rate corresponds to the amount of filter aid that, per observation period, passes from the filter module reservoir 108, which is assigned to a filter module 102, onto the filter elements 106 of the filter module 102 and adheres there. This amount of filter aid is measured by the decrease in weight of the filter module reservoirs 108 (including the material contained therein), which is determined using the container scale.

[0195] A stirring rate of 2.5 kg therefore means that during a period of 60 seconds, 2.5 kg of filter aid from the filter module reservoir 108 reaches the filter elements 106 of the filter module 102 and remains there.

[0196] By decreasing the target turbulence rate r as a function of the filter aid loading M at load factors f less than 1.0, the time between two turbulence processes (and thus also the time between two cleaning processes on the filter elements 106) can be extended, which saves the compressed air required for turbulence.

[0197] The load factors f are preferably determined and set for each filter module 102 during each commissioning of the filter device 100, as these load factors f depend very strongly on the type and quantity of paint used. If in doubt, the highest load factor of 1.0 is assigned to a filter module 102. In this case, the target agitation rate r remains constant regardless of the filter aid loading M and thus remains constant throughout the entire operating time of the filter device 100.

[0198] For heavily loaded filter modules 102, a high load factor f in the range of preferably at least 0.9 is generally recommended in order to adequately protect the filter elements 106 of these filter modules 102.

[0199] Preferably, the control software in the control device 128 sets the target stirring rate r to a minimum value of, for example, 0.80 kg per observation period (of preferably 60 seconds).

[0200] If the observation period is extended, for example to 90 seconds, the minimum target stirring rate is preferably also increased accordingly, for example to 1.2 kg per observation period.

[0201] The required target turbulence rate is preferably recalculated cyclically after each observation period. This observation period is, for example, 60 seconds.

[0202] After each such observation period, the target stirring rate r of the stirring device 122 of a filter module reservoir 108 is recalculated for the next observation period, taking into account the current filter aid occupancy M.

[0203] The number of stir-up events per observation period, required to achieve the determined target stir-up rate r, is also dynamically recalculated after the end of each observation period. This calculation takes into account the amount of filter aid that was transferred from the filter module reservoir 108 to the filter elements 106 of the filter module 102 per stir-up event during the observation period. If this amount of filter aid stirred up per event is large, the number of stir-up events per observation period is reduced accordingly.

[0204] The number of turbulence shocks per observation period therefore depends both on the filter aid loading M and on the measured amount of filter aid which, per turbulence shock, passes from the filter module reservoir 108 to the filter elements 106 of the filter module 102.

[0205] The operation of a turbulence device 122 of a filter module reservoir 108, which operates with compressed air pulses, is shown schematically in the flow diagram of Fig. 7.

[0206] The turbulence control begins with a system start-up 244.

[0207] In step 246, the filter module reservoir 108 is first filled with filter aid.

[0208] Step 248 checks whether a cleaning process is currently being carried out on the filter elements 106 of the filter module 102.

[0209] If this is the case, the stirring process is interrupted in step 250, and the execution returns to step 246.

[0210] If this is not the case, step 252 checks whether the agitation process should be started manually via a user interface. Such a user interface could, for example, be a touchscreen with a visual representation of the filter device 100 or at least a part of it. In this case, the user interface is also referred to as a "visualization".

[0211] If a stirring process is to be started manually via the user interface, a release request is sent to the operations management of the filter device 100 in step 254.

[0212] When the operational management releases the stirring process (step 256), the compressed air valve 150 (see Fig. 1) is opened in step 258.

[0213] Step 260 checks whether the stirring process has been manually stopped via the user interface.

[0214] If this is not the case, execution returns to step 258.

[0215] If the stirring process has been manually stopped via the user interface, the compressed air valve 150 is closed in step 262.

[0216] The execution then returns to step 246.

[0217] If step 252 determines that the stirring process should not be started manually via the user interface, a cyclic stirring process is started in step 264.

[0218] In step 266, the pause time is waited out, that is, the time between two stirring processes, which, as described above, has been determined by the control device 128 taking into account the current filter aid occupancy M and the current amount of filter aid that is transferred from the filter module reservoir 108 to the filter elements 106 per stirring process.

[0219] After the break time has elapsed, in step 268 a request for the release of a stirring process is submitted to the operations management.

[0220] Once the swirling process has been released by the operations management (step 270), the compressed air valve 150 is opened in step 272.

[0221] In step 274, a predetermined duty cycle of the turbulence device 122 is awaited.

[0222] In step 276, after the specified duty cycle has elapsed, the compressed air valve 150 is closed.

[0223] The execution then returns to step 264.

[0224] In the embodiment of a filter device 100 described above and shown in Figs. 1 to 5 for separating particles from a raw gas stream 120 containing particles, each filter module 102 is assigned a separate filter module reservoir 108.

[0225] In contrast, in the second embodiment of such a filter device 100 shown in partial view in Fig. 8, several filter modules 102 are assigned to the same filter module reservoir 108, which receives the material (filter aid and separated overspray particles) cleaned by the filter elements 106 of this plurality of filter modules 102.

[0226] In order to add the filter aid to the raw gas stream 120 without the risk of the filter aid entering the application areas of the paint booths, and to be able to collect filter aid cleaned together with separated particles from the filter elements 106, in the embodiment shown in Fig. 8, each group of several, for example three or more, filter modules 102 is assigned a common filter module reservoir 108, which extends in a longitudinal direction 278 of the filter module reservoir 108 over the entire length of the, for example three or more, assigned filter modules 102.

[0227] In this case, the filter module reservoir 108 is essentially trough-shaped and comprises an upper inlet section 280 and a mixing section 282 that adjoins the inlet section 280 downwards.

[0228] The entrance section 280 is bounded by two end walls 284 running perpendicular to the longitudinal direction 278 and two (not shown) opposing side walls extending from one end wall 284 to the other end wall 284 and inclined to the vertical at an angle of at least approximately 30°.

[0229] The mixing section 282, which adjoins the inlet section 280 downwards, is essentially cylindrical and has a cylindrical section-shaped outer wall extending over a circumferential angle of, for example, approximately 270°, the upper edges of which connect to the lower edges of the side walls of the inlet section 280 of the filter module reservoir 108, so that the mixing section 282 opens upwards towards the inlet section 280.

[0230] In this embodiment, the stirring device 122 comprises a mixing device 286, for example in the form of a paddle mixer 288, for thoroughly mechanically mixing the material cleaned by the filter elements 106 of the various filter modules 102, which fills the mixing section 282 up to a fill level 290. The mixing device 286 is arranged in the mixing section 282 of the filter module reservoir 108 and preferably comprises a rotating shaft 292, which extends parallel to the longitudinal direction 278 and is rotatably mounted on the end walls 284 of the filter module reservoir 108 by means of bearings 294 about a horizontal axis of rotation 296 running parallel to the longitudinal direction 278.

[0231] One end of the rotary shaft 292 is guided fluid-tight through one of the end walls 284 of the filter module reservoir 108 and coupled to a rotary drive 298 (for example an electric drive motor) arranged outside the filter module reservoir 108.

[0232] Several mixing tools 300 are arranged on the rotating shaft 292 in a rotationally fixed manner with it; these can be designed, for example, as paddles 302 or as plowshares.

[0233] The inner contour of the mixing section 282 of the filter module reservoir 108 is adapted to the outer contour of the mixing tools 300 of the mixing device 286 such that the mixing tools 300 sweep over a mixing area during a complete rotation of the rotating shaft 292 of the mixing device 286 about its axis of rotation 296, the outer contour of which essentially corresponds to the inner contour of the mixing section 282 of the filter module reservoir 108.

[0234] Preferably, the mixing device 286 sweeps over substantially the entire mixing section 282 of the filter module reservoir 108 during one complete revolution about its axis of rotation 296.

[0235] The mixing movement of the mixing device 286, driven by the rotary drive 298, destroys the bonding forces between the particles of which the material in the filter module reservoir 108 consists, and causes the material to be mixed in the longitudinal direction 278 of the rotating shaft 292.

[0236] Due to the mixing movement, there are no concentration differences within the filter module reservoir 108, and in particular, the ratio of fresh filter aid on the one hand and filter aid cleaned by the filter elements 106 and overspray particles on the other hand is essentially the same everywhere in the filter module reservoir 108.

[0237] In order to supply fresh filter aid to the filter module reservoir 108, a material inlet 304 for fresh filter aid is provided on an end wall 284 of the filter module reservoir 108, which is connected via one of the branch lines 174 already described above (see Fig. 2) to one of the supply lines 176 of the filter aid supply system 168.

[0238] A material outlet 306 is provided on the end wall 284 of the filter module reservoir 108 opposite the material inlet 304 for fresh filter aid, which is connected to one of the branch lines 212 described above (see Fig. 4) and is connected via this branch line 212 to one of the disposal lines 214 of the filter aid disposal system 208.

[0239] Through this material outlet 306, no enriched filter aid can be discharged from the filter module reservoir 108 with overspray, in order to maintain a substantially constant fill level 290 in the filter module reservoir 108 despite the supply of fresh filter aid through the material inlet 304.

[0240] Alternatively, the filter module reservoir 108 can be completely emptied and then refilled by supplying fresh filter aid. Instead of individual paddles 302 projecting radially from the rotating shaft 292, the mixing tools 300 of the mixing device 286 can also be designed as a helix coaxial with the rotating axis 296 of the mixing device 286.

[0241] In particular, it may be provided that the mixing device 286 is equipped with two helixes with opposite directions of rotation.

[0242] Such helixes can have the same pitch but different radii.

[0243] The opposing direction of rotation of the two helixes ensures particularly good mixing of the material present in mixing section 282.

[0244] By actuating the mixing device 286, material located in the filter module reservoir 108 is stirred up and introduced into the raw gas stream 120, which enters the filter modules 102 assigned to the filter module reservoir 108.

[0245] In this way, the target turbulence rate r determined for the filter modules 102 in the manner described above can be achieved without the need for additional turbulence using compressed air pulses.

[0246] Based on the target value for the turbulence rate r calculated for the filter modules 102, the control device 128 calculates the necessary rotational frequency of the mixing device 286, which is required to achieve this target value.

[0247] After each observation period of, for example, 60 seconds, the required rotational frequency for the next observation period is recalculated. As described above, the target value for the agitation rate r depends on the load factor f of the respective filter module 102 and on the filter aid loading M of the respective filter module 102.

[0248] In particular, it can be provided that the target value for the resuspension rate r decreases during the resuspension process. The more filter aid is already present on the filter elements 106 of a filter module 102, the lower the target value for the resuspension rate r becomes.

[0249] Since the rotational frequency of the mixing device 286 can only be determined jointly for all filter modules 102 which are assigned to the same filter module reservoir 108, in the case of target agitation rates r varying between the filter modules 102, the arithmetic mean of these target agitation rates r is used to determine the rotational frequency of the mixing device 286.

[0250] The operation of a mixing device 286 designed as a stirring device 122 of a filter module reservoir 108 is shown schematically in the flow diagram of Fig. 9.

[0251] The turbulence control begins with a system start-up 308.

[0252] In step 310, the initial filling of the filter module reservoir 108 with filter aid is completed.

[0253] In step 312, it is checked whether a cleaning process is currently being carried out on the filter elements 106 of the filter modules 102 assigned to the filter module reservoir 108.

[0254] If this is the case, the rotational speed of the mixing device 286 is set to the last set value in step 314. The execution of the operating control program then returns to step 310.

[0255] If in step 312 it is determined that no cleaning process is currently being carried out on the filter elements 106 of the filter modules 102 assigned to the filter module reservoir 108, in step 316 it is checked whether a target value is fixed for the rotational frequency of the mixing device 286.

[0256] If this is the case, in step 318 the mixing device 286 is operated at the fixed rotational frequency.

[0257] In this process, the rotational frequency of the mixing device 286 is not adjusted to the degree of loading of the raw gas stream 120 with particles to be separated, to a target stirring rate r determined for the filter modules 102 assigned to the filter module reservoir 108, and to a filter aid loading M of the filter modules 102 assigned to the filter module reservoir 108 (step 320).

[0258] Finally, the execution of the operational control program returns to step 310.

[0259] If in step 316 it is determined that no fixed target value for the rotational frequency of the mixing device 286 is specified, the mixing device 286 is operated in step 322 (preferably continuously) at a rotational frequency which is recalculated after each observation period (of, for example, 60 seconds).

[0260] In step 324, the rotational frequency for the mixing device 286 of the filter module reservoir 108 is recalculated taking into account the target agitation rates r and the filter aid loading M of the filter modules 102 assigned to the filter module reservoir 108, and, if necessary, also taking into account the strength of the raw gas flow 120 through the filter modules 102 assigned to the filter module reservoir 108, and the rotary drive 298 of the mixing device 286 is operated according to the newly determined rotational frequency.

[0261] Finally, the execution of the operational control program returns to step 310.

[0262] Furthermore, the second embodiment of a filter device 100 shown in Fig. 8 corresponds in terms of structure, function and method of manufacture to the first embodiment shown in Figs. 1 to 5, to whose preceding description reference is made in this respect.

[0263] All subsequent statements regarding further functions of the filter device 100 apply to the first embodiment shown in Figs. 1 to 5, as well as to the second embodiment shown in Fig. 8 and the third embodiment shown in Figs. 13 and 14.

[0264] In each cleaning process in which filter aid is cleaned off the filter elements 106 of a filter module 102, the total amount of filter aid and separated particles cleaned off by the filter elements 106 (the "blasted off" amount of filter aid and particles) is determined.

[0265] This is achieved, for example, by having the control device 128 calculate the difference between the weight of the material in the filter module reservoir 108 after the cleaning process and the weight of the material in the filter module reservoir 108 before the cleaning process. The weight of the material in the filter module reservoir 108 can be measured, for example, using a container scale.

[0266] If the amount of filter aid removed from the filter elements 106 during a cleaning process falls below a predetermined target value, the control device 128 issues a fault message. The control device 128 and the container scale thus form components of a monitoring device 327 for monitoring the amount of filter aid removed during a cleaning process and for generating a fault message if the removed amount of filter aid falls below a target cleaning value.

[0267] This monitoring of the amount of material removed during a cleaning process is preferably only carried out if the cleaning process is triggered automatically. Such automatic triggering of a cleaning process can occur, for example, if the weight of the material in the filter module reservoir 108 falls below a predefined starting level for the cleaning process.

[0268] The specified target value, below which a fault message is issued, can be calculated, for example, according to the following formula:

[0269] Target value of weight monitoring = filter aid occupancy M on the filter elements / number of pulse valves ■ 25%.

[0270] The filter aid loading M of the filter elements 106 is determined, for example, by calculating the difference between the weight of the material in the filter module reservoir 108 before the start of the turbulence processes and the weight of the material in the filter module reservoir 108 after the last turbulence process.

[0271] If, for example, a total of 25 kg of filter aid has been stirred up by the agitation processes and remains on the filter elements 106 of a filter module 102, and if, for example, 10 discharge valves 140 are present, then the target value for weight monitoring is 25 kg / 10 ■ 25% = 0.625 kg. If the amount of material cleaned during a cleaning process falls below the determined target value of 0.625 kg several times, for example twice in succession, the control device 128 issues a fault message, which reads, for example, as follows: "Check the valve!"

[0272] The dust sensor 135 in the exhaust duct 134 monitors the airflows which enter the recirculated air circulation from the filter modules 102 and the airflows which leave the filter device 100 as exhaust air.

[0273] The dust sensor 135 is preferably arranged upstream of the exhaust fan 136 in the exhaust duct 134.

[0274] Depending on the width of the exhaust duct 134, it may also be useful to use a dust sensor 135 with an extended sensor rod or several dust sensors 135, for example two or more dust sensors 135, for monitoring.

[0275] It is advantageous if the length of the sensor rod of the dust sensor 135 extends over at least one third, particularly preferably over at least two thirds, of the channel width of the exhaust air duct 134, that is, its horizontal orientation perpendicular to the flow direction of the exhaust air.

[0276] Therefore, if a sensor rod has a maximum length of 1 m, at least two separate dust sensors 135 should be used for monitoring from a channel width of 3 m or more.

[0277] If several dust sensors 135, for example sensor rods, are used, dust can be considered detected if the detection limit of at least one of the dust sensors 135 is exceeded. Alternatively or additionally, it can also be provided that an average value, for example an arithmetic mean, is calculated from the signals of several dust sensors 135 and this average value is compared with a threshold value for the detection of dust.

[0278] The dust sensors 135 can be calibrated to a predefined dust value (for example, in mg / m³) by means of a defined dust task. 3 ) be calibrated.

[0279] Alternatively, a dimensionless output value from the dust sensor 135 can also be used for evaluation in the control device 128.

[0280] A sensor element of a dust sensor 135 can, for example, operate according to the triboelectric effect. Such sensor elements are offered, for example, by the company ENVEA SA at 111, Boulevard Robespierre, CS 80004, 78304 Poissy CEDEX 4, France, under the name ProSens.

[0281] For example, such a sensor element transmits a current signal in the range of 4 to 20 mA to the control device 128. The control device 128 assigns a raw value for the dust load to the current signal of the sensor element. For example, a maximum raw value of 100,000 dust units, preferably a maximum raw value of 50,000 dust units, can be assigned to the maximum current signal of a sensor element. Optionally, a relay switching contact integrated into the sensor element can also be used.

[0282] Furthermore, to assess the dust load detected by the dust sensor 135, it is necessary to determine the background noise level for each sensor element. This can be done, for example, by averaging the raw value determined by the control device 128 over an averaging period of, for example, 5 minutes, while the filter device 100 is operating properly, i.e., without increased dust load in the exhaust duct 134. The background noise level determined in this way can, for example, be in the range of 500 to 2,000 dust units.

[0283] In the case of small leaks, which may occur, for example, due to faulty assembly of individual filter elements 106 in a filter module 102, such as by tightening a locking screw with insufficient torque or if a locking screw is not tightened at all, minor dust leaks from a filter module 102 into the exhaust duct 134 are to be expected primarily during a cleaning process carried out on the filter elements 106 in question.

[0284] If the dust sensor 135 detects an exceedance of the background noise by, for example, a factor of at least 5, a leakage count of a filter module 102, during whose cleaning the exceedance occurred, is preferably incremented by 1. When determining the timing between the exceedance of the background noise and the execution of the cleaning process on a filter module 102, it is taken into account that, depending on the arrangement of the filter modules 102 and the distance of the dust sensor 135 from the respective filter module 102, a delay occurs between the time of the release of filter aid from a filter module 102 and the time of detection of the released filter aid by the dust sensor 135. Such a delay time can be, for example, two seconds.

[0285] The assignment of an exceedance of the background noise at the dust sensor 135 to a specific filter module 102 is therefore carried out in the control device 128 via a software evaluation, in which it is checked which filter module 102 was in cleaning mode at the time of detection of the exceedance of the background noise or within the time interval which is around the delay time before the detection time and extends to the detection time.

[0286] If the same filter module 102 is later assigned another exceedance of the background noise at the dust sensor 135, the leakage count value assigned to the filter module 102 increases again by 1.

[0287] If the leakage count of a filter module 102 reaches a predetermined warning value, for example 5 or preferably 2, a warning message is generated by the control device 128. However, the filter device 100 is preferably not restricted in production operation due to such a warning message. Rather, it is merely noted that maintenance and inspection of the relevant filter module 102 should be carried out during the next production break.

[0288] If a filter module 102, whose leakage count is at least 1, is cleaned again without the filter module 102 being assigned an exceedance of the background noise at the dust sensor 135, the leakage count is reduced by 1 or set directly to 0.

[0289] Only when the leakage count of a filter module 102 falls below the warning limit again can a previously generated warning message be acknowledged without any maintenance and inspection of the filter module 102 having been carried out.

[0290] Furthermore, the operating control software in the control device 128 can be configured to trigger a cleaning process on a filter module 102 whose leakage count has reached a predetermined threshold, for example, 1, in order to check whether such a cleaning process on the filter module 102 in question results in the background noise being exceeded at the dust sensor 135. If this verification is negative, the leakage counter of the filter module 102 in question can be reduced by 1 or reset to 0.

[0291] In principle, it is possible for several filter modules 102, whose exhaust air is supplied to a dust sensor 135, to be in cleaning mode simultaneously. In this case, the leakage count value for each of the simultaneously cleaned filter modules 102 is increased by 1. If one of these filter modules 102 is cleaned again and the background noise level at the dust sensor 135 is exceeded, the leakage count value of the filter module 102 in question is increased by 1.

[0292] If one of these filter modules 102 is cleaned again and the background noise at the dust sensor 135 is not exceeded, the leakage count value of the filter module 102 in question is reduced by 1 or set to 0.

[0293] In this way, a misattribution of a leakage event to a filter module 102, which was cleaned at the same time as a defective filter module 102, can be avoided.

[0294] In very rare cases, filter failure or filter breakage may occur during the operation of the filter device 100.

[0295] A filter breakage on a filter element 106 can be caused by a material defect or by improper handling of a filter element 106 during its cleaning.

[0296] Occasionally, it is necessary to clean the filter module reservoirs 108 internally. This involves using a plastic scraper to remove deposits from the inner walls of the filter module reservoir 108, consisting of a mixture of filter aid and separated particles. Improper handling during this process can damage one of the filter elements 106. Filter failure can occur if one of the filter modules 102 is subjected to an excessively high raw gas flow rate. Due to the high flow velocities of the raw gas, the filter aid contained in the raw gas stream 120 can cause abrasion at the pleat tips of the filter elements 106. This can occur particularly when using nonwoven filter elements.

[0297] One reason for an excessively high velocity of the raw gas flow 120 could be incorrectly adjusted shut-off valves in the air ducts on the clean gas side of the filter modules 102.

[0298] Another reason could be that the raw gas stream 120 from an application area is distributed across several filter modules 102, but then one or more filter elements in only one of these filter modules 102 are replaced. After the replacement, the newly installed filter elements 106 exhibit a significantly lower pressure drop when flowing through them with the raw gas stream 120 than the filter elements 106 of the same filter module 102 and of the other filter modules 102 that have been in use for a longer period. As a result, the raw gas stream 120 is no longer distributed evenly across the filter modules 102, but rather the filter module 102 with the new filter elements 106 experiences a significantly higher flow rate.

[0299] If a filter breakage or filter failure occurs, filter aid continuously enters the base body 130 of the filter module 102 and the downstream channels, in particular the exhaust air channel 134, through the corresponding leakage point of a filter module 102.

[0300] Due to this introduction of filter aid into the clean gas side of a filter module 102, the continuously measured background noise of the dust sensor 135 is significantly elevated from the time of failure. If the warning limit is exceeded for a period of time longer than a predefined filter failure threshold, for example, longer than 60 seconds, the control device 128 issues a warning message, for example, the warning message "Filter breakage / filter failure".

[0301] Since a filter failure or filter breakage leads to a significantly higher ingress of filter aid into the base body 130 of the filter modules 102 and into the exhaust air duct 134 than an incomplete seal on one of the filter elements 106, the cause of the filter failure or filter breakage is preferably remedied as quickly as possible in order to keep the contamination of the air ducts downstream of the filter modules 102 as low as possible.

[0302] If a warning message regarding a filter failure or filter breakage is not acknowledged within a specified acknowledgment time, which is, for example, one hour, it may be stipulated that the coating system to which the filter device 100 is assigned will have its entry authorization withdrawn.

[0303] Furthermore, it may be provided that the filter device 100 is put into a sleep mode, which will be explained in more detail below.

[0304] Due to the potential for significant contamination of the filter device 100 in the event of a filter failure or filter breakage, it may also be provided that the infeed release of the coating system is withdrawn immediately upon the occurrence of the warning message indicating a filter breakage or filter failure and / or that the filter device 100 is put into a sleep mode immediately after the issuance of the warning message indicating a filter breakage or filter failure.

[0305] Since the signal of the dust sensor 135 is continuously above the warning value in the event of a filter failure or filter breakage, and the warning value is no longer only exceeded during a cleaning process on a defective filter module 102, the failure cannot be clearly assigned to a specific filter module 102 in the event of a filter breakage or filter failure.

[0306] However, it may still be possible to indicate the faulty filter module 102 if, during cleaning of the relevant filter module 102, the warning value is exceeded to a significantly greater extent than before or after the cleaning process on the relevant filter module 102.

[0307] Using the filter aid disposal system 208 described above and the filter aid supply system 168 described above, a material exchange is carried out at a filter module reservoir 108 as required, as described below.

[0308] Material exchange at a filter module reservoir 108 occurs when the material contained in the filter module reservoir 108, a mixture of filter aid and separated particles, can no longer be sufficiently stirred up.

[0309] If the specified target resuspension rate r is not reached during a resuspension process, a material exchange counter for the relevant filter module reservoir 108 is incremented by 1. When this material exchange counter reaches a set threshold value, the material exchange is carried out at the relevant filter module reservoir 108.

[0310] Alternatively or additionally, it can also be provided that the material exchange at a filter module reservoir 108 takes place when the production zone of the coating system, to which the filter modules assigned to the respective filter module reservoir are assigned, has been passed through by a predetermined number of workpieces, for example, vehicle bodies. This ensures that a material exchange at a filter module reservoir takes place at the latest when the predetermined number of workpieces that have passed through the respective production zone has been reached.

[0311] Instead of a predetermined number of workpieces, a predetermined number of workpiece carriers, for example skid frames, can also be defined, whereby a material exchange then takes place at a filter module reservoir when the predetermined number of workpiece carriers that have passed through the production zone in question has been reached.

[0312] Each time a workpiece passes through the relevant production zone, the workpiece counter for the corresponding filter module reservoir 108 is incremented by 1. When this workpiece counter reaches a preset threshold, the material exchange at the relevant filter module reservoir 108 is carried out.

[0313] Alternatively or additionally, it can also be provided that when a workpiece carrier, for example a skid frame, has passed through the relevant production zone, a workpiece carrier counter for the relevant filter module reservoir 108 is incremented by 1. When this workpiece carrier counter reaches a preset threshold, the material exchange at the relevant filter module reservoir 108 is carried out.

[0314] It can happen that the material contained in a filter module reservoir 108, a mixture of filter aid and separated particles, is difficult to stir up immediately after refilling with new filter aid or only a short time after refilling. In such a case, the material exchange counter reaches the set threshold value very quickly, which would actually trigger a material exchange at the filter module reservoir 108 in question, even though such a material exchange is not yet necessary.To prevent such unnecessary material exchange, it can be provided that the material exchange at a filter module reservoir 108 is only carried out if not only the material exchange counter has reached the set threshold value, but also the workpiece counter and / or the workpiece carrier counter for the relevant filter module reservoir 108 has reached a predetermined minimum value.

[0315] This specified minimum value can correspond to a certain fraction of the number of workpieces or workpiece carriers, at the latest when a material exchange is carried out.

[0316] For example, it may be provided that the minimum value of the workpiece counter or the workpiece carrier counter required for carrying out a material exchange at a filter module reservoir 108 corresponds to at least one sixth, in particular at least one third, and especially preferably at least half, of the number of workpieces or the number of workpiece carriers at which a material exchange is carried out at the filter module reservoir 108 in question.

[0317] The introduction of this additional condition for material exchange prevents unnecessary material exchange from being carried out in filter module reservoirs 108, whose contents are difficult to stir up, shortly after refilling with fresh filter aid.

[0318] First, the material present in the filter module reservoir 108 is conveyed by the filter aid disposal system 208 into the collection reservoir 220 of one of the disposal units 218 and from there into the collection container 238. The filter aid disposal system 208 described above serves to dispose of the filter aid for a coating plant with six production zones (Primer 1, Base Coat 1, Clear Coat 1, Primer 2, Base Coat 2 and Clear Coat 2), but has only three disposal units 218, whereby each filter module reservoir 108 can be emptied into any of the three disposal units 218.

[0319] The disposal units 218 can operate in parallel, but only those filter module reservoirs 108 assigned to different production zones can be emptied simultaneously. This means that the filter modules 102 assigned to the filter module reservoirs 108 being emptied simultaneously are intended for separating particles from different painting phases. Therefore, only one filter module reservoir 108 can be emptied per production zone at a time.

[0320] Each disposal unit 218 is assigned a FIFO ("First In, First Out") list (for example, in the control device 128) into which the filter module reservoirs 108 to be emptied are entered. The control software running on the control device 128 decides which filter module reservoir 108 is entered into which FIFO list.

[0321] The rule is that filter module reservoirs 108, which are assigned to the same production zone, are entered into the same FIFO list.

[0322] Furthermore, taking into account the aforementioned rule, a filter module reservoir 108 is always entered into the shortest FIFO list in order to complete material disposal as quickly as possible.

[0323] The sequence of a material disposal process using the filter aid disposal system 208 is shown schematically in the flow diagram of Fig. 11. After the filter device 100 is started in step 323, the operating sequence is in step 325, in which the suction blowers 230 of the disposal units 218 are switched off or are in a bypass mode, in which they are not in fluid contact with the respective associated collection reservoir 220.

[0324] In step 326, a filter module reservoir 108, in which the specified target turbulence rate r has not been reached once or several times, reports to the material disposal.

[0325] In step 328, the relevant filter module reservoir 108 is entered at the next free position in the FIFO list of one of the disposal units 218, taking into account the rules explained above.

[0326] In step 330, the disposal route from the filter module reservoir 108, which is at position 1 in a FIFO list, to the collection reservoir 220 of the disposal unit 218 assigned to this FIFO list is opened by opening the valve 226 between the disposal line 214 assigned to the respective production zone (Primer 1, Base Coat 1, Clear Coat 1, Primer 2, Base Coat 2, Clear Coat 2) and the filter aid branch line 224 of the disposal unit 218 in question.

[0327] Furthermore, the suction blower 230 of the relevant disposal unit 218 is started and / or brought into fluid contact with the interior of the collection reservoir 220 of the relevant disposal unit 218.

[0328] In step 332, the material disposal system signals its readiness to carry out a disposal process to the filter module reservoir 108 to be emptied. If, in step 334, the filter module reservoir 108 has given its release and the pinch valve 210 assigned to the filter module reservoir 108 to be emptied has been opened, in step 336 the disposal of the material from the filter module reservoir 108 to be emptied into the collection reservoir 220 of the disposal unit 218 to be emptied begins.

[0329] If the weight of the material remaining in the filter module reservoir 108 falls below a predetermined threshold, the pinch valve 210 assigned to the filter module reservoir 108 is closed in step 338.

[0330] Then, in step 340, the disposal line 214 is flushed.

[0331] When the flushing of the disposal line 214 is complete, in step 342 the contents of the collection reservoir 220 are transferred to the collection container 238 by opening the slide valve 236 using compressed air from the compressed air control line 240.

[0332] When this cleaning process is completed at the collection reservoir 220 of the relevant disposal unit 218, in step 344 the emptied filter module reservoir 108 is removed from the FIFO list of the relevant disposal unit 218, thus reducing the number of entries in this FIFO list by 1.

[0333] In step 346, the system checks whether the number of entries in the FIFO list is at least 1. If so, the control program returns to step 330, where the disposal route to the filter module reservoir 108 to be emptied is opened. This reservoir is now at position 1 in the FIFO list, and this further material disposal process is carried out as described above. If the check in step 346 shows that there are no longer any entries in the FIFO list of disposal unit 218, the suction blower 230 of disposal unit 218 is initially operated at a standby frequency lower than the operating frequency and, after a predetermined transition time, is switched off or put into a bypass mode in which the suction blower 230 is no longer in fluid contact with the collection reservoir 220 of disposal unit 218 (step 348).

[0334] The execution of the control program for material disposal then returns to step 325.

[0335] After a filter module reservoir 108 has been emptied, the filter module reservoir 108 is refilled with fresh filter aid from a supply silo 182 using the filter aid supply system 168.

[0336] Although the coating system to which the filter device 100 is assigned comprises six production zones (Primer 1, Base Coat 1, Clear Coat 1, Primer 2, Base Coat 2 and Clear Coat 2), the filter aid supply system 168 has only three supply units 180, each supply unit 180 being capable of filling each filter module reservoir 108. However, of the filter module reservoirs 108 assigned to the same production zone, only one filter module reservoir 108 can be filled at any given time.

[0337] Each of the supply units 180 is assigned a FIFO ("First In, First Out") list, into which the filter module reservoirs 108 to be filled are entered by the control software running on the control device 128.

[0338] The control software enters the filter module reservoirs 108 into the FIFO lists according to the following rules: Filter module reservoirs 108 that are assigned to the same production zone are entered into the same FIFO list.

[0339] Taking this rule into account, a filter module reservoir 108 to be filled is always entered into the shortest current FIFO list in order to complete the supply of fresh filter aid as quickly as possible.

[0340] The process of a material supply operation carried out by means of the filter aid supply system 168 is shown schematically in the flow diagram of Fig. 10.

[0341] After the filter device 100 is started in step 350, the blowers 194 of the supply units 180 are initially in a switched-off state or in a bypass mode, in which the air conveyed by the blowers 194 is discharged through the respective associated exhaust air line 196 with the flap 200 open (step 352).

[0342] If, in step 354, a filter module reservoir 108 to be filled has registered with the material supply, the relevant filter module reservoir 108 is entered by the control software in step 356 at the next free position in one of the FIFO lists of the supply units 180, taking into account the rules explained above.

[0343] In step 358, a supply route from the rotary valve 184 of a supply unit 180 to the filter module reservoir 108 to be filled is opened by opening the valve 190 between the filter aid branch line 188 of the supply unit 180 and the supply line 176, which is assigned to the respective production zone (Primer 1, Base Coat 1, Clear Coat 1, Primer 2, Base Coat 2, Clear Coat 2), and, if necessary, the pinch valves 178 located in the supply line 176 between the valve 190 and the branch line 174 of the filter module reservoir 108. Furthermore, the blower 194 of the supply unit 180 is started at a standby frequency.

[0344] In step 360, the filter module reservoir 108, which is to be filled, is notified that the material supply is ready.

[0345] If the relevant filter module reservoir 108 has given the release in step 362 and the pinch valve 172 assigned to the relevant filter module reservoir 108 in the branch line 174 of the relevant filter module reservoir 108 has been opened, in step 364 the frequency of the blower 194 of the relevant supply unit 180 is increased to an operating frequency, the rotary valve 184 is put into operation and the flap 200 in the exhaust air line 196 is closed and the flap 202 in the delivery line 198 is opened.

[0346] This begins the filling of the filter module reservoir 108 with fresh filter aid from the supply silo 182 of the respective supply unit 180.

[0347] When the specified filling weight in the filter module reservoir 108 is reached, a message is generated in step 366 indicating that the pinch valve 172 assigned to the filled filter module reservoir 108 has been closed. This terminates the material supply to the filter module reservoir 108.

[0348] In step 368, the rotary valve 184 is taken out of service and the filter aid supply line 186 and the used supply line 176 are flushed by means of air from the blower 194.

[0349] In step 370, the filled filter module reservoir 108 is removed from the FIFO list of the relevant supply unit 180, and the number of entries in this FIFO list is reduced by 1. In step 372, it is checked whether the number of entries in the relevant FIFO list is at least 1.

[0350] If this is the case, the execution of the control program continues at step 358 by opening a disposal route from the rotary valve 184 to the filter module reservoir 108, which is now at position 1 of the relevant FIFO list. A material supply operation is then carried out at this additional filter module reservoir 108 as described above.

[0351] If the check in step 372 shows that the FIFO list of the relevant supply unit 180 no longer contains an entry, in step 374 the damper 202 in the supply line 198 is closed, the damper 200 in the exhaust air line 196 is opened, and the frequency of the blower 194 is reduced to the standby frequency. After a predetermined waiting period, the blower 194 is switched off.

[0352] The execution of the control program then returns to step 352.

[0353] To further reduce the consumption of energy and compressed air during the operation of the filter device 100, it can be provided that at least one of the filter modules 102 of the filter device 100 can be put into a sleep mode (also called "Eco Mode" or "eco mode") by the control device 128 when the filter module 102 in question is not currently being cleaned and is filled with a predetermined minimum amount of the filter aid, and when the filter module reservoir 108 associated with the filter module 102 is neither being emptied nor filled with filter aid, and when no treatment process that increases the particle concentration in the raw gas stream 120 will be carried out on a workpiece within a predetermined pause time. When a filter module 102 has been put into sleep mode, no agitation processes and no cleaning processes are carried out on the filter module 102.If a filter module reservoir 108 assigned to the filter module 102 is equipped with a mixing device 124, for example with a paddle mixer 288, such a mixing device is also stopped.

[0354] Ideally, no energy or compressed air is consumed by the filter module 102, which is in sleep mode, and preferably also by the filter module reservoir 108 assigned to this filter module 102.

[0355] Preferably, the sleep mode of a filter module 102 is automatically activated during production breaks via the control software running on the control device 128.

[0356] The following conditions apply to the activation of sleep mode on a filter module 102, either individually or preferably in any combination:

[0357] The option to put at least one filter module 102 of the filter device 100 into sleep mode must be enabled in the control software of the control device 128.

[0358] Another requirement is that it can be expected that during a given production break period no workpiece to be coated, in particular no vehicle body to be coated, will enter an application area from which a raw gas stream 120 loaded with particles to be separated will reach the filter module 102 to be switched to sleep mode.

[0359] Such a predetermined production break duration can, for example, be at least three minutes, preferably at least five minutes. A further requirement for switching a filter module 100 into sleep mode is that the filter module 102 is in an operational state, that no cleaning process is being carried out on the filter elements 106 of the filter module 102, and that no material disposal or supply process is being carried out at a filter module reservoir 108 assigned to the filter module 102.

[0360] Another requirement for switching a filter module 102 into sleep mode is that a predetermined minimum amount of filter aid is present on the filter element 106 of the filter module 102. This predetermined minimum amount of filter aid can be, for example, at least 5 kg, preferably at least 10 kg.

[0361] The possibility of transferring a filter module 102 into sleep mode can be activated, for example, via a configuration bit in a status display of a user interface of the control software running on the control device 128.

[0362] After this activation, at predetermined time intervals, it is checked for each filter module 102 whether the prerequisites selected from the above requirements for transferring the filter module 102 into sleep mode are met.

[0363] When the conditions for transferring a filter module 102 into sleep mode are met, the filter module 102 switches to sleep mode, and the stirring and cleaning processes at the filter module 102 and / or at the filter module reservoir 108 assigned to the filter module 102 are prevented.

[0364] If the filter module reservoir 108 assigned to the filter module 102 has a mixing device 124, for example in the form of a paddle mixer 188, the operation of the mixing device 124 is also stopped. As soon as a workpiece, for example a vehicle body, registers for a coating process in an application area from which a particle-laden raw gas stream 120 reaches the filter module 102 which is in sleep mode, the relevant filter module 102 is automatically switched back to normal operation by the control software.

[0365] This is the case, for example, when a vehicle body is located in the entry area of ​​a paint booth.

[0366] The switching procedure between normal operation and sleep mode is shown schematically in the flowchart of Fig. 12.

[0367] After the filter device 100 is started in step 376, stirring and cleaning processes are carried out in step 378 with the parameters determined in the manner described above.

[0368] If, in step 380, the transition of at least one filter module 102 into sleep mode has been enabled via the user interface of the control software, the possible switching of a filter module 102 into sleep mode is activated.

[0369] If, in step 382, ​​information is received indicating that a production break is expected between two consecutive workpieces to be processed, in particular between two consecutive vehicle bodies, which exceeds a minimum break time of, for example, at least three minutes, preferably at least five minutes, all filter modules 102 assigned to the production zone in which the aforementioned production break is expected are switched to sleep mode (step 384). In step 386, it is checked whether the filter modules 102 to be switched to sleep mode are operational, whether they are in normal operation, and whether the amount of filter aid adhering to the filter elements 106 of such a filter module 102 is more than a minimum amount of, for example, at least 5 kg, preferably at least 10 kg.

[0370] If these conditions are met, in step 388 the relevant filter modules 102 are put into sleep mode and the stirring and cleaning processes that would otherwise be carried out on the filter modules 102 put into sleep mode are suppressed.

[0371] If a filter module reservoir 108 assigned to the filter modules 102 in sleep mode is equipped with a mixing device 124, for example with a paddle mixer 288, this mixing device 124 is switched off.

[0372] When the control program receives information that an object to be treated, for example a vehicle body, is located in the entry area of ​​a paint booth, from whose application area a raw gas stream 120 laden with particles reaches filter modules 102 that are in sleep mode, the relevant filter modules 102 are switched from sleep mode back to normal operation. The execution of resuspension and cleaning processes on these filter modules 102 is reactivated.

[0373] If a filter module reservoir 108 is assigned to the filter modules 102 to be returned to normal operation, which is equipped with a mixing device 124, for example with a paddle mixer 288, then this mixing device 124 is also put back into operation.

[0374] The execution of the control program then continues at step 378. A third embodiment of a filter device 100 for separating particles from a particle-containing raw gas stream 120, shown in Figures 13 and 14, differs from the second embodiment of such a filter device 100 shown in Figure 8 in that not several filter modules 102 are assigned to the same filter module reservoir 108, but rather each filter module reservoir 108 is assigned only a single filter module 102, wherein the filter module reservoir 108 receives the material (filter aid and separated overspray particles) cleaned by the filter elements 106 of the respective assigned filter module 102.

[0375] As can be seen from Fig. 13, in this third embodiment each filter module 102 comprises a housing 104, in the interior 105 of which several filter elements 106 are arranged.

[0376] On the clean gas side, the filter module 102 comprises a base body 130.

[0377] Below the housing 104 of the filter module 102 is the respective associated filter module reservoir 108.

[0378] The filter module reservoir 108 rests on a container scale 127, which includes one or more load cells 129.

[0379] The container scale 127 enables monitoring of the quantity of filter aid which is contained in the interior 116 of the filter module reservoir 108.

[0380] The load cells 129 of the container scale 127 are preferably each mounted on one or more compensator devices, in particular vibration compensators, which, for example, comprise or are formed from an elastomeric material, in order to decouple vibrations transmitted into a frame 131 of the filter module 102 from the load cells 129. The filter module reservoir 108 also has a material outlet 306, preferably arranged centrally, through which a mixture of filter aid and separated overspray arranged in the filter module reservoir 108 can be extracted or otherwise discharged.

[0381] Furthermore, the filter module reservoir 108 includes a material inlet 304, through which fresh filter aid can be supplied to the filter module reservoir 108.

[0382] A vortexing device 122 is arranged on and in the filter module reservoir 108, which includes a mixing device 286 in the form of a paddle mixer 288.

[0383] The paddle mixer 288 shown in Fig. 14 comprises a rotating shaft 292 on which several paddles 302 are arranged.

[0384] The surface plane of each paddle 302 is preferably rotated by an angle of 30° to 60°, preferably by an angle of approximately 45°, relative to the longitudinal axis of the shaft 292, so that the conveyance of the filter aid to the center of the filter module reservoir 108 is made possible.

[0385] Each paddle 302 is preferably arranged offset in the circumferential direction of the rotating shaft 292 by an angle of 75° to 165°, particularly preferably by an angle of approximately 120°, with respect to the respective adjacent paddles 302, which are arranged in the direction of the longitudinal axis of the rotating shaft 292 at a distance from the paddle 302 in question.

[0386] The arrangement of the paddles 302 along the longitudinal axis of the rotating shaft 292 is preferably mirror-symmetrical with respect to a transverse median plane 378 of the rotating shaft 292, which is oriented perpendicular to the longitudinal axis of the rotating shaft 292 and intersects the rotating shaft 292 centrally. Furthermore, the paddle mixer 288 comprises a rotary drive 298, preferably an electric motor, for driving the rotating shaft 292 into a rotary motion, wherein the rotary drive 298 is preferably arranged outside the filter module reservoir 108.

[0387] The raw gas 120, which is not loaded with overspray particles, enters the housing 104 through an inlet section 380. This housing can be covered by a cover 384 when the filter module 102 is at rest. The gas then flows along an inflow direction 382 into the interior 105 of the filter module reservoir 108, where it picks up filter aid material agitated by the paddle mixer 288. The filter aid material binds the overspray particles contained in the raw gas stream 120.

[0388] The raw gas containing the filter aid is then passed through the filter elements 106 of the filter module 102, whereby the filter aid together with the bound overspray particles settles on the surfaces of the filter elements 106, forming a filter cake.

[0389] On the clean gas side of the filter elements 106, the filtered clean gas stream passes through the base body 130 of the filter module 102 into an exhaust air line 132 (shown only schematically) and from there into a common exhaust air duct of several filter modules 102.

[0390] Furthermore, the embodiment of a filter module 102 and a filter module reservoir 108 of a filter device 100 shown in Figs. 13 and 14 corresponds in terms of structure, function and manufacturing method to the second embodiment shown in Fig. 8, to whose preceding description reference is made in this respect.

[0391] Since in this third embodiment only one filter module 102 is assigned to each filter module reservoir 108, the rotational frequency of the mixing device 286 in the form of the paddle mixer 288 is determined in the third embodiment by the Sol I swirl rate r of the filter module 102 assigned to the filter module reservoir 108 and not by an arithmetic mean of the target swirl rates r of several filter modules 102.

Claims

Patent claims 1. Filter device for separating particles from a particle-containing raw gas stream (120), wherein the filter device (100) comprises: at least one filter module (102); a filter module reservoir (108) associated with the filter module (102) for receiving a filter aid; and a swirling device (122) for swirling filter aid received in the filter module reservoir (108), characterized in that the filter device (100) comprises a control device (128) by means of which at least one parameter of the operation of the swirling device (122) can be changed depending on a filter aid requirement associated with the at least one filter module (102), a filter aid loading (M) associated with the at least one filter module (102) and / or a target swirling rate (r) associated with the at least one filter module (102).

2. Filter device according to claim 1, characterized in that at least one of the at least one variable parameter by means of the control device (128) is a cycle time within which a swirling process is repeated, or a swirling duration during which a swirling process is carried out.

3. Filter device according to one of claims 1 or 2, characterized in that at least one of the at least one parameter that can be changed by means of the control device (128) is a rotational frequency of a mixing tool (300) of a mixing device (124).

4. Filter device according to one of claims 1 to 3, characterized in that a target stirring rate (r) is reduced with decreasing filter aid requirement.

5. Filter device according to one of claims 1 to 4, characterized in that a target stirring rate (r) is reduced with increasing filter aid loading (M).

6. Filter device according to one of claims 1 to 5, characterized in that the filter device (100) comprises several filter modules (102), each filter module (102) being assigned to one of several production zones, the filter device (100) comprising a filter aid disposal system (208) comprising several disposal units (218), each disposal unit (218) being connected to each of the filter module reservoirs (108) assigned to the filter modules (102), the fluid connections between the filter module reservoirs (108) and the disposal units (218) being switchable by means of the control device (128) such that several disposal units (218) are simultaneously in fluid connection with each of the filter module reservoirs (108), the filter modules (102) assigned to these filter module reservoirs (108) being assigned to different production zones.

7. Filter device according to claim 6, characterized in that each disposal unit (218) is assigned a FIFO list, wherein a filter module reservoir (108) to be emptied is entered in the same FIFO list as a previously entered filter module reservoir (108) which is assigned to a filter module (102) that is assigned to the same production zone as the filter module (102) which is assigned to the newly entered filter module reservoir (108), if such a filter module reservoir (108) is present in one of the FIFO lists of the disposal units (218). and, moreover, the filter module reservoir (108) to be emptied is entered into the shortest of all FIFO lists of disposal units (218).

8. Filter device according to one of claims 1 to 7, characterized in that the filter device (100) comprises several filter modules (102), each filter module (102) being assigned to one of several production zones, the filter device (100) comprising a filter aid supply system (168) comprising several supply units (180), each supply unit (180) being connected to each of the filter module reservoirs (108) assigned to the filter modules (102), the fluid connections between the filter module reservoirs (108) and the supply units (180) being switchable by means of the control device (128) such that several supply units (180) are simultaneously in fluid connection with each of the filter module reservoirs (108), the filter modules (102) assigned to these filter module reservoirs (108) being assigned to different production zones.

9. Filter device according to claim 8, characterized in that each supply unit (180) is assigned a FIFO list, wherein a filter module reservoir (108) to be filled is entered in the same FIFO list as a previously entered filter module reservoir (108) which is assigned to a filter module (102) that is assigned to the same production zone as the filter module (102) which is assigned to the newly entered filter module reservoir (108), if such a filter module reservoir (108) is present in one of the FIFO lists of the supply units (180), and otherwise the filter module reservoir (108) to be filled is entered in the shortest of all FIFO lists of the supply units (180).

10. Filter device according to one of claims 1 to 9, characterized in that a cleaning device (143) for cleaning a mixture of filter aid and separated particles from the filter module (102) is associated with the at least one filter module (102), wherein the filter device (100) further comprises a monitoring device (327) for monitoring a quantity of the filter aid cleaned during a cleaning process carried out by means of the cleaning device (143) and for generating a fault message if the cleaned quantity of the filter aid falls below a cleaning setpoint value once or several times.

11. Filter device according to claim 10, characterized in that the cleaning setpoint is determined as a function of an amount of the filter aid arranged on the filter module (102) before the cleaning process.

12. Filter device according to one of claims 1 to 11, characterized in that the filter device (100) comprises at least one dust sensor (135) which is arranged in the flow path of the gas cleaned of particles downstream of a filter module (102), wherein the control device (128) increments a leakage counter of the filter module (102) when a dust quantity exceeding a threshold value is detected by means of the dust sensor (135) and the filter module (102) in question is being cleaned of a mixture of filter aid and separated particles during the detection time or when the filter module (102) in question was the last filter module (102) that was cleaned of a mixture of filter aid and separated particles before the detection time.

13. Filter device according to claim 12, characterized in that the leakage counter of the filter module (102) is lowered by the control device (128) when a cleaning process has been carried out on the filter module (102) and no dust quantity exceeding the threshold has been detected by the at least one dust sensor (135) during the cleaning process and within a predetermined grace period after the cleaning process.

14. Filter device according to one of claims 1 to 13, characterized in that a filter module (102) of the filter device (100) can be switched to a sleep mode by the control device (128) if the filter module (102) in question is not cleaned and is covered with a predetermined minimum amount of the filter aid and if the filter module reservoir (108) associated with the filter module (102) is neither emptied nor filled with filter aid and if no treatment process increasing the particle concentration in the raw gas stream (120) will be carried out on a workpiece within a predetermined pause time.

15. Filter device according to claim 14, characterized in that when a filter module (102) is put into sleep mode, the agitation device (122) and / or a cleaning device (143) associated with the filter module (102) are not put into operation.

16. Method for operating a filter device (100) for separating particles from a particle-containing raw gas stream (120), wherein the filter device (100) comprises at least one filter module (102), a filter module reservoir (108) associated with the filter module (102) for receiving a filter aid, and a swirling device (122) for swirling filter aid received in the filter module reservoir (108). characterized in that at least one parameter of the operation of the agitation device (122) is changed by means of a control device (128) of the filter device (100) depending on a filter aid requirement assigned to the at least one filter module (102), on a filter aid loading (M) assigned to the at least one filter module (102) and / or on a target agitation rate (r) assigned to the at least one filter module (102).

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