DE202010012437U1 - filter means - Google Patents

Abstract

A filter device (10) for cleaning debris entraining gas, comprising:
- At least one filter unit (12) having at least one filter surface on a Rohgasseite, a foreign body-containing raw gas stream (44) can be fed, wherein the raw gas stream (44) and / or the filter surface filtration aids are fed and wherein attached to the filter surface filtration aids and / or Foreign substances are cleanable; such as
A fluid bed arrangement (55), in which a carrier fluid stream (54) can be generated, such that cleaned filtration auxiliaries and / or foreign substances are held at least partly as filtration aerosol in an environment of the filter unit (12) and / or can re-attach to a filter surface ,

Description

The The present invention relates to a filter device for cleaning foreign body entraining gas, in particular a dry filtration filter device.

With Dry filtration working filter devices are becoming diverse for cleaning exhaust air or other exhaust gases (hereinafter generally referred to as exhaust air) used in installations of different types Industries are incurred. A very special advantage of dry filters towards wet filter devices, e.g. B. washout systems, is the relatively simple processing of accumulated filtered out Foreign bodies, since these are not in liquid phases bound incurred.

Indeed Problems arise if foreign bodies are contained in the exhaust air are that have sticky character. This is for example the Case, if the exhaust air contains tarry dusts, or in the case of exhaust air of paint shops, especially wet paint. Such sticky foreign substances are in fact preferred in the pores of the filter and clog them gradually. Because of their stickiness they bind firmly to the filter surface and can be so with the usual dry filters used cleaning systems that work with compressed air, not remove more from the filter surface. The filter loses so fast its cleaning ability and needs to be replaced become.

It is known to add filtration aids when using dry filters for filtering exhaust air containing foreign substances of sticky character. This can be done upstream of the dry filter by injecting filtration aids in the raw gas stream supplied to the dry filter, or a filter surface on the raw gas side of the dry filter can be coated with filtration aids before it comes in contact with foreign bodies (so-called "precoating"). The filtration aids should combine with the sticky foreign bodies in the exhaust air and ensure that formed on the filter surface of filtration aids and foreign bodies agglomerates are deposited, which can be easily detached again with the usual Abreinigungsverfahren. An example of the addition of filtration aids immediately into the raw gas stream upstream of the dry filter is in the DE 42 11 465 C2 disclosed. The pre-coating of the filter surfaces with filtration aids, for example, from DE 197 15 195 A1 known. In both cases, it is also provided to collect material accumulating after a cleaning of the filter and, if necessary, to add it to the crude gas stream again after a treatment.

From the DE 199 24 130 A1 and DE 103 61 266 A1 a method is known in which, after cleaning the filter unit accumulating material is collected in a collecting container and this collected material is whirled by blowing compressed air in the collecting container such that it attaches to the filter surface again.

task It is the object of the present invention to provide an improved filtering device to provide the described type, in particular a more effective use allows the filtration aids.

to Solution to this problem is inventively a Filter device for cleaning foreign bodies mitführendem Gas proposed with the following characteristics: It is at least one Filter unit provided with at least one filter surface on a raw gas side containing a foreign body Raw gas stream can be fed, wherein the raw gas stream and / or Filtering aids can be fed to the filter surface are. Filtration aids attached to the filter surface and / or foreign substances are cleanable. Besides, one is Fluid bed arrangement provided in which a carrier fluid flow can be generated is such that purified filtration aids and / or foreign substances at least in part as a filtration aerosol in an environment of Filter unit are held and / or back to a filter surface can attach. The term "filtration aerosol" is used this generally for the designation of a mixture of solid and / or liquid suspended particles in the carrier fluid stream used without a limitation of the diameter of the suspended particles to imply. Up to what size the particles can grow before, due to their gravity are discharged from the aerosol layer depends first Line on the properties of the carrier fluid stream. It is with a suitable adjustment of the carrier fluid flow without Other possible, particles up to diameters of more than 100 μm in suspension.

The Filter surface is cleanable the sense that at the Filter surface adhering material from the filter surface at a cleaning procedure, usually at intervals is carried out, is removable again. The temporal Distances are usually after the loading of the Set filter surface and be chosen so that a predetermined maximum pressure drop across the filter stage is not exceeded.

The addition of filtration aids - examples of such filtration aids are stone dust or other mineral dusts - leads to the formation of agglomerates of excipients with foreign bodies attached thereto. Such agglomerates are much less sticky than the pure foreign bodies, so that such agglomerates much easier as which are removable from the filter surface than the pure foreign body. In this way, an effective use of working with dry filters filter devices also succeeds for the purification of exhaust air containing sticky foreign bodies, such as the resulting in wet or Trocklackieranlagen exhaust air.

In order to in sufficient time sufficient agglomeration the foreign body with the filtration aids takes place, It is cheap, a comparatively large amount to add to filtration aids. This also sets sure that the entire filter surface is within short time with a layer of filtration aids with possibly attached foreign bodies that the filter surface protects. However, this approach means that within a single cleaning cycle of the filter unit only a small percentage of the added filtration aids agglomerates has formed. One is, of course, anxious about the excipients to use as efficiently as possible, d. H. preferably all added filtration aids in agglomerates of Fil trationshilfsstoffen implement with attached foreign bodies. That is why the Idea emerged that accumulating after cleaning the filter Mixture of filtration aids and foreign bodies several times to use again until as complete as possible Implementation, d. H. Occupation of filtration aids with foreign bodies, took place.

The re-addition of deposited on a cleaning Material to the raw gas or the filter surface has but proved problematic because of the filter surface deposited and on the ground or in a separate container collected material often caking structures forms that are difficult to isolate. Even that Injecting compressed air into the material collected at the bottom with Aim to whirl this material so far that it will turn attached to the filter surface leads only partially to satisfactory results. The invention therefore proposes a completely new approach. Instead of at a Cleaning detached from the filter surface Material in a container or at the bottom of the raw gas chamber to collect and collect there, should this material as possible stay close to the filter surface. This allows this material on the one hand fast again comes into contact with the raw gas stream and on the other hand remains in contact with the filter surface. In this way can form further agglomerates, or already existing Agglomerates by addition of foreign bodies or other agglomerates continue to grow. Also, the cleaned up Quickly re-attach material to the filter surface and thus form a protective coating. The described operations can be virtually continuous expire. Shutting down the device for the purpose of cleaning and reassignment of the filter surface is no longer necessarily required.

It has shown that with the help of a fluid bed holding the material detached from the filter surface is possible. The material forms in the fluidized bed Aerosol layer derived from a carrier fluid flow "in the levitation "is held. In the fluid bed after Type of a known as a fluidized bed or "fluidized bed" Arrangement works, flows through a flow the carrier fluid, which is usually upwards is directed, thus counteracting gravity, the individual Particles of foreign bodies, filtration aids and solid phase formed from agglomerates formed therefrom, and interacts with these in such a way that the individual particles in a fluidized state, as it were "suspended" are. This fluid bed arrangement can be adjusted so that those formed from foreign bodies, filtration aids and from them Agglomerates formed solid phase in optimal contact with others get entrained by the raw gas flow entrainment can and thus very efficiently forms further agglomerates or for growth already formed agglomerates leads. One stops the fluidized solid phase near the filter surface, also succeeds, after a cleaning in a short time Time again with a protective layer to prove.

about the flow of carrier fluid can be adjusted, which maximum mass density agglomerates of filtration aids and foreign bodies may still have fluidized to be worn. Exceed the agglomerates this critical mass density, they are gradually falling further down and finally completely out of the fluid bed out. In this way it is possible to already saturated Agglomerates for further use for addition other foreign substances or for occupancy of the filter surface is no longer desirable from the filter device remove by falling out down. simultaneously can to the extent in which used agglomerates fall out of the fluid bed, continuously unused filtration aids be added. The filter device does not need to shut down to replace used filtration aids.

Preferably, in operation, the fluid bed assembly forms a filtration aerosol layer of filtration aids, debris, and agglomerates of filtration aids having foreign bodies attached thereto, extending vertically from a lower limit at or slightly below the lower surface of the filter unit to an upper limit at or slightly above the upper surface the fil unit extends or even beyond. In one example, the filtration aerosol layer may extend down to 90 cm, preferably up to 60 cm, and most preferably up to 50 cm below the bottom of the filter unit.

When Carrier fluid is in particular a carrier gas (z. As air) in question, which on the raw gas side of the filter unit is available. The carrier fluid may be the raw gas stream themselves, in the simplest case essentially by the raw gas stream forming gas. In such cases, the Fluid bed arrangement preferably a Verwirbelungsanordung, by the on the raw gas side, in particular in the filtration aerosol layer, an upward, preferably turbulent flow can be generated. The turbulence arrangement should be in the raw gas stream support any existing tendency to form vertebrae in such a way that a fluidized bed is formed in the filtration aerosol layer, which ensures that the filtration aerosol stable in This layer is maintained, but still a good mix within the layer takes place to promote agglomeration or on the filter surface efficiently a protective coating to be able to form.

Preferably For example, the fluid bed assembly may further include a carrier fluid introduction assembly through which the raw gas side of the filter unit with carrier fluid can be acted upon. The carrier fluid may additionally form the carrier fluid stream to the raw gas stream. Further For example, the carrier fluid introduction assembly may also be formed be that they cause a turbulence of the introduced carrier fluid leads. It is also advantageous if the carrier fluid is introduced in such a way that an upward directed carrier fluid flow. An advantage in use one by a swirl / carrier fluid introduction assembly generated carrier fluid stream is that the carrier fluid stream can be adjusted - for example, by appropriate Design and / or control of the swirling / carrier fluid introduction arrangement - that particles that are heavier than a predetermined critical Mass density, no longer held in suspense and out of the Filtration aerosol layer fall out.

The Swirling / Trägerfluideintraganordnung can, for example comprise a ring line arranged below the filter unit, which with at least one - preferably several - nozzles having provided nozzle arrangement. The ring line can be acted upon during operation with carrier fluid, in such a way that in operation downstream of the nozzle assembly a directed towards the filter unit and contrary to gravity acting Trä gerfluidstrom trains. Alternatively, for example below the filter unit with a fluidizing (For example, slits) provided Fluidisierboden be. This Fluidisierboden is from its underside with Carrier fluid applied, so that the carrier fluid flows through the fluidizing openings and downstream of the fluidizing tray to the filter unit directed and the gravitational counteracting carrier fluid flow formed.

The Swirling / carrier fluid introduction assembly may be used as a be provided in operation continuously operating device. If the Trägerfluideintraganordnung a sufficient generates strong carrier fluid flow, the strength can the carrier fluid flow largely independent of Be adjusted raw gas flow.

In According to one embodiment, the filter device may comprise at least one a raw gas space facing the raw gas side of the filter unit is, defining housing with at least one in the Rohgasraum opening Rohgaszuströmöffnung include. The raw gas stream passes through the Rohgaszuströmöffnung into the raw gas room. The housing is then usually also define a clean gas room, the clean gas side of the filter unit facing, with an opening into the clean gas discharge opening for filtered clean gas.

It has been shown to be in a favorable embodiment the Rohgaszuströmöffnung approximately at height or may be located slightly below the filter unit. This is especially beneficial if a coming from below Carrier fluid flow is provided because of this carrier fluid stream then mixed below the filter unit with the raw gas stream and entrains the foreign bodies contained therein. Since the Carrier fluid stream also carries the excipients, provides this for efficient agglomeration between filtration aids and foreign bodies.

In a further embodiment, the housing may have at least one further inflow opening opening into the raw gas space, through which filtration aids can be supplied. The supplied filtration aids may be pure or slightly contaminated with foreign substances filtration aids. It is favorable if the further inflow opening is also arranged at the level or somewhat below the filter unit. Filtrationshilfsstoffe can be supplied through this further inflow at predetermined intervals or as a continuous stream of filtration aids to replace precipitated material from the fluidized bed. An optionally required first assignment of the filter device can also take place through the further inflow opening. Possibly. also slightly contaminated filtration aids can be supplied by this further inflow, which accumulate after a cleaning of the filter unit and are diverted from the fluidized bed. The latter are easily contaminated with foreign bodies cleaned filtration aids, but only so little is occupied or agglomerated with foreign bodies that they can attach even more foreign bodies.

alternative or additionally may also be another filtration adjuvant feeder be provided, which upstream of the filter unit opens into the crude gas stream. Through this further filtration aid feed device On the one hand, fresh filtration auxiliaries can be added to the crude gas stream but also such filtration aids, which are branched off from the fluid bed and easily with foreign bodies are contaminated.

In According to one embodiment, the inflow opening be arranged for the raw gas stream so that the raw gas stream at an angle of about 90 degrees into the carrier fluid stream empties. It is particularly favorable if the crude gas stream opens below the filter unit in the carrier fluid flow.

The Filter device may further associated with one of the raw gas side Collection container for non-reusable particles exhibit. Non-reusable particles are "saturated" agglomerates from filtration aids and foreign bodies that are so extensive are occupied with foreign bodies that further attachment of foreign bodies no longer possible efficiently is. Such saturated agglomerates have a significant greater mass density than the foreign bodies alone and also not or only weakly with foreign bodies occupied filtration aids. Depending on the setting of the carrier fluid flow is it possible to set a maximum mass density of particles, which can still be kept floating in the fluid bed. As soon as the agglomerates become heavier than this mass density, they will they can fall out of the filtration aerosol layer and can collected in the collecting container underneath be, preferably at a lowest point a disposal opening has, deducted by the material from collecting container is. This can be done for example by a vacuum conveyor happen.

Of the For example, catch container can be below a below the filter unit arranged and substantially funnel-shaped be arranged trained portion of the housing.

Around the removal of unusable agglomerates from the collecting container To facilitate, in addition, the collection container have a fluidizing arrangement through which in the collecting container befindliches material is acted upon with gas, which is his Flowability is maintained. The fluidizing device can be operated continuously or for a short while a removal of accumulated in the collection container material.

the Collecting container may further include a conveyor be assigned, through which material from the collection container peelable and the Filtrationsaerosolschicht and / or the raw gas stream upstream the filter unit can be fed. Such a conveyor can in particular when restarting the filter device Helpful, because it allows particles to shut down the device and the inevitable collapse the carrier fluid stream from the filtration aerosol layer fall into the collecting container when restarting remove the device from the container and the Filtrationsaerosolschicht or supply the raw gas stream again. In general, that is after switching off the device Material in the collecting container from the filtration aerosol layer in itself still be useful as a filtration adjuvant. Without the Conveyor would have to be disposed of. The Conveyor can pneumatically with overpressure, z. B. in the form of a low-pressure injector, with negative pressure as Vacuum conveyor or fluidized with pressure in the manner of a solids pump, in particular a solid membrane pump, work.

The Cleaning may be performed by a cleaning unit associated with the filter unit respectively. The cleaning device may be a compressed air cleaning unit have, above the filter unit on the clean gas side is arranged such that the filter unit in countercurrent principle Compressed air is acted upon to the filter unit on the Crude gas to deposit deposited material. If the filter unit having a plurality of filter elements, the Druckluftabreinigungseinheit be so controlled that alternately one after the other always only one Part of the filter elements is cleaned, so that a possible uniform amount of filtered filtration aids / foreign bodies results that must be held in suspense.

Preferably the filter unit has at least one filter element which is designed as a rigid body filter.

In According to one embodiment, the filter element may be a base body of sintered material, preferably sintered Polyethylene (PE) particles as a main component contains. The main body can be finished with a surface coating be provided containing polytetrafluoroethylene (PTFE) particles.

In an alternative embodiment, the filter element from an arrangement of PE bodies, in particular PE tubes, be formed, wherein on the PE body in each case a filter membrane made of PTFE is laminated.

In According to one embodiment, the housing may be at least a lateral and closed by a corresponding lid Housing opening, the height the filter elements is arranged and through which the filter elements can be used in the upper and lower filter module. The housing can for example, in a region surrounding the filter unit cylindrical or rectangular and in a lower funnel-shaped Go over the area at the lowest point, if necessary, the collection container followed.

When Filtrationshilfsstoffe come especially stone meal, z. B. limestone flour or other mineral dusts in question.

Of the Filter unit may additionally one more - preferably comprising a washout system or a cyclone separator - pre-separation stage be deposited in the coarse impurities already.

Of the Filter unit may also have a - preferably a memory filter comprehensive - further downstream filter stage. By regular review of downstream filter stage may be a failure or deterioration the filter unit are detected and the filter unit if necessary be replaced. The downstream filter stage also prevents that uncleaned exhaust air comes out of the system.

• – Vorrichtung zur Beseitigung von Luftverunreinigungen in einer Nasslackieranlage,
• – Vorrichtung zur Beseitigung von Luftverunreinigungen in einer Trockenlackieranlage,
• – Vorrichtung zur Beseitigung von Luftverunreinigungen in einer Laserstrahlschweißanlage oder einer sonstigen Schweißrauchagsaugungsanlage,
• – Vorrichtung zur Beseitigung von Verunreinigungen in Rauchgasen, insbesondere in Rauchgasen, die bei Verbrennungsprozessen anfallen (bei solchen Verbrennungsprozessen entstehen nicht selten teerhaltige oder rußartige Produkte, die aus dem Abgas als Verunreinigungen abgeschieden werden müssen);
• – Vorrichtung zur Beseitigung von Luftverunreinigungen in einer Anlage zur Hohlraumversiegelung,
• – Vorrichtung zur Beseitigung von Luftverunreinigungen in einer Anlage zum Verkleben von Metallteilen;
• – Vorrichtung zur Beseitigung von gasförmigen Verunreinigungen in einem Abgasstrom unter Zugabe von chemisorptiven Filtrationshilfsstoffen, welche mit den gasförmigen Verunreinigungen chemisch reagieren (beispielsweise kann in Abgasen enthaltenes Schwefeldioxid, SO₂, oder HCl-Gas durch Zugabe von Calciumhydroxid, Ca(OH)₂, als Filtrationshilfsmittel wirksam am Trockenfilter abgeschieden werden, dabei findet die Chemisorption gleichzeitig mit mit Abscheidung von festen oder flüssigen Aerosolen aus dem Abgas statt).

Preferred fields of application of the filter device described are devices in which exhaust air is produced which contains sticky and / or tarry foreign substances. It has been shown that the device according to the invention can be installed, above all, in installations of one of the following types and performs valuable services:

• Device for the removal of air pollutants in a wet painting plant,
• - apparatus for the removal of air pollutants in a dry painting plant,
• Apparatus for removing airborne contaminants in a laser welding machine or other welding smoke suction equipment,
• - Device for the elimination of impurities in flue gases, especially in flue gases, which are incurred in combustion processes (in such combustion processes are often tarry or sooty products that must be separated from the exhaust gas as impurities);
• Device for the removal of air pollutants in a cavity sealing installation,
• - Device for the removal of air pollutants in a plant for the bonding of metal parts;
• - Device for the removal of gaseous impurities in an exhaust gas stream with the addition of chemisorptive filtration aids which react chemically with the gaseous impurities (for example, contained in exhaust gases sulfur dioxide, SO ₂ , or HCl gas by adding calcium hydroxide, Ca (OH) ₂ , as Filtration aids are effectively deposited on the dry filter, while the chemisorption takes place simultaneously with deposition of solid or liquid aerosols from the exhaust gas instead).

The Invention will be described below with reference to an embodiment explained in more detail. It shows:

1 in a side view of a filter device for cleaning foreign body entraining gas according to an embodiment; and

2 the device off 1 in one opposite the view 1 90 degree rotated side view.

1 and 2 show in each rotated by 90 degrees to each other side views a filter device 10 for cleaning debris entraining gas according to an embodiment. The device 10 includes a filter unit 12 (in 1 not shown in 2 is one of the filter elements 14 the filter unit 12 indicated). The filter unit 12 is above a Rohgaszuströmöffnung 16 in an overview omitted half upper part of a housing 18 appropriate. The filter unit 12 comprises a plurality of filter elements designed as rigid body filters 14 , which are fixed to a common upper bracket and parallel to each other in the vertical direction, as in 2 is indicated schematically, the one of the filter elements 14 at its installation position shows.

In the in 1 and 2 pictured lower part of the housing 18 , which is a raw gas space 15 encloses, are next to the Rohgaszuströmöffnung 16 yet another inflow opening 20 as well as a flap 22 educated. All these openings 16 . 20 . 22 lie substantially at the same height in an annular upper area 18a of the lower housing part 18 , In one below this area 18a adjoining area 18b takes the case 18 the shape of a funnel with downwardly tapered side walls. Down closes to the housing 18 a collection container 24 in which non-usable material is collected before passing through a at the lowest point of the collection container 24 arranged disposal opening 26 and a disposal funnel 28 in a vacuum conveyor 30 directed and disposed of, see the arrow 32 in 1 , The disposal funnel 28 is usually through one Valve 34 closed at its lowest point and is only briefly opened when material from the container 24 should be discharged. For disposal of the in the collection container 24 collected material, which is usually very heavily coated with sticky foreign bodies and may store there for a relatively long time, is located in the collection container 24 a sloping fluidising floor 36 that has a connection 38 is supplied with air. To the connection 38 is an only schematic with 40 Connected blower connected, via the pressurized air into the fluidization 36 is directed. The one in the fan 40 generated air flow is adjusted so that, although in the collecting container 24 collected material on the one hand so far loosened that it is very free-flowing and thus easily on the disposal opening 26 it is removable, but that material on the other hand not again from the collection container 24 in the case 18 or in the raw gas space 15 can get.

The schematic with the arrow 44 designated raw gas stream, which carries foreign matter with which, with the device 10 to be separated occurs via the Rohgasszuströmöffnung 16 in the case 18 enclosed raw gas space 15 one on top of the raw gas side of the filter unit 12 is limited. The crude gas stream 44 will be after entering the raw gas room 15 to the filter unit 12 transported. On the the Rohgaszuströmöffnung 16 opposite side of the housing 18 there is another inflow opening 20 , by which filtration aids, usually stone meal, from a reservoir, not shown, into the raw gas space 15 can be directed. The stream of filtration aids is in 1 with an arrow 45 designated.

In a lower region of the funnel-shaped housing region 18b there is a connection 48 that goes horizontally through the housing 18b running ring line 46 communicates. The ring line 46 is located above the collection container 24 and in particular always above the in the collecting container 24 collected material. With the connection 48 is another fan 50 connected in 2 also indicated only schematically. The fan 50 can, for example, as well as the blower 40 , comprising a side channel compressor. In a preferred embodiment, the blower 50 during operation of the device 10 operated continuously.

In the ring line 46 are several nozzles 52a . 52b . 52c . 52d trained in 2 are indicated schematically. About this one nozzle arrangement 52 forming nozzles 52a . 52b . 52c . 52d Comes pressurized air through the blower 50 generated and over the connection 48 in the ring line 46 is introduced, and forms after deflection through the inner walls of the funnel-shaped housing portion 18b a substantially vertically upwardly directed carrier fluid stream 54 , This carrier fluid stream 54 is indicated in the figures by dashed circular arc-shaped curves. The carrier fluid stream 54 moves from the nozzle assembly 52 starting at an upward speed determined by that of the blower 50 generated gas pressure and the geometric arrangement of the nozzles 52a . 52b . 52c . 52s as well as their arrangement to the housing 18 , loop 46 with nozzle arrangement 52 , Connection 48 and blowers 50 belong to a fluid bed arrangement 55 which is in operation of the blower 50 the carrier fluid stream 54 generated.

At the height of Rohgaszuströmöffnung 16 the carrier fluid stream combines 54 with the raw gas stream 44 , This leads to the fact that in the raw gas stream 44 entrained foreign body with the carrier fluid stream 54 be carried up and so to the filter unit 12 be transported. If necessary, the further inflow opening 20 Filtrationshilfsstoffe supplied, wherein the flow of filtration aids 45 also with the carrier fluid stream 54 mixed and thus the filtration aids from the carrier fluid stream 54 taken and up to the filter unit 12 be transported. On the way to the filter unit 12 these streams are mixed together 54 . 44 and 45 , This leads to the fact that in the raw gas stream 44 entrain foreign bodies with the filtration aids and form agglomerates, which then on the filter surfaces of the filter unit 12 be attached.

The filter unit 12 is assigned a not shown in the figures Druckluftabreinigungseinheit located on the clean gas side of the filter unit 12 above the filter elements 14 located. At certain intervals be the compressed air cleaning unit aufschlagt a respective filter element 14 , so that this experiences a pressure surge from its pure gas side. The surge results in that on the raw gas side of the respective filter element 14 attached material, as described either pure filtration aids or agglomerates of filtration aids with foreign bodies attached thereto, from the filter element 14 detached and falls down due to its gravity.

Once the cleaned particles (as I said, filtration aids or agglomerates of filtration aids with foreign matter attached thereto) after their detachment from the filter element 14 in the influence of the carrier fluid flow 54 Not only do they experience a downward force due to their gravity, but also an upward force due to the upward flow of the carrier fluid. This leads to these particles, at least as long as they do not exceed a certain critical mass density, do not move further down, but rise again until the gravity and the flow of carrier fluid 54 exerted force balance. The consequence is that at a certain height, which is roughly the height of the filter unit 12 up to the height of the Rohgaszuführöffnung 16 down, forming a relatively stable filtration aerosol layer. In this Filtrationsaerosolschicht the filtration aids, the foreign body contained in the raw gas and also the agglomerates formed from the same are held in suspension. This applies at least to agglomerates which are not yet saturated, ie those agglomerates whose mass density has not yet become greater than the critical mass density due to excessively high occupancy with foreign bodies.

Preferably, the flow rate of the carrier fluid stream is 54 and / or the flow rate of the raw gas stream 44 chosen so large that in the carrier fluid stream 54 at least from the union with the raw gas stream 44 Turbulence is forming. Although the filtration aerosol layer remains stable overall, the individual particles of this layer are well mixed by the turbulence, which promotes efficient agglomeration or reoccupation of the filter surfaces with filtration aid.

Once a cleaning of each filter element 14 the filter unit 12 has taken place in the filtration aerosol layer sufficiently many particles of filtration aid to cause a further efficient agglomeration with foreign bodies, which are carried in the raw gas stream. On a supply of fresh filtration aids over the further feed opening 20 can then be waived in principle. However, in the device 10 those particles which have become heavier as a result of the attachment of numerous foreign bodies to the filtration aid are no longer held in the filtration aerosol layer and fall down into the collecting vessel 24 , This effect is quite desirable, because such particles are no longer able to accumulate more foreign bodies and therefore basically useless for further use as a filtration aid. The loss of filtration aids occurring during operation can be compensated by fresh filtration aids, which are supplied via the further inflow opening 20 be supplied.

At first startup of the device 10 The best way to do that is to first use the blower 50 is put into operation, so that the carrier fluid flow 54 formed. Thereafter, via the further inflow opening 20 Filtrationshilfsstoff supplied. On the one hand, this leads to the formation of a stable filtration aerosol layer and, on the other hand, to the fact that there is already a first protective covering of filtration aid on the filter surfaces of the filter unit 12 formed. Thereafter, the crude gas stream 44 over the Rohgaszuführöffnung 16 switched on. As soon as further operation, the pressure drop over a respective one of the filter elements 14 the filter unit 12 becomes larger than intended operation (or after a predetermined period of operation), finds a cleaning of this filter element 12 instead of. This provides additional material for the filtration aerosol layer. A further addition of fresh filtration adjuvants can be dispensed with at the latest from the time when all the filter elements are once cleaned, except for the addition of filtration aids to compensate for losses of spent filtration aids discharged from the filtration aesole layer.

The device 10 also has an injector device 58 on. This injector device 58 includes a blower 60 , which is a pressurized air stream 62 to a low pressure injector 64 and from there into the collection container 24 supplies. On the low pressure injector 64 opposite side of the collection container 24 opens a low-pressure riser 66 in the collection container 24 , The low pressure riser 66 leads upwards and flows approximately at the level of Rohgaszuführöffnung 16 in the raw gas room 15 , Alternatively, the low pressure riser could 66 also at a location further upstream in the raw gas stream 44 lead.

The injector device 58 is helpful when the device 10 is put back into operation after a business interruption. Will the device 10 In fact, even with completely occupied filter surfaces in the filtration aerosol layer, filtration aid will generally still be present, which is not yet completely saturated and thus could still be used further. As soon as the blower 50 is turned off, the carrier fluid stream falls 54 together, with the result all the material in the filtration aerosol layer in the collecting container 24 falls and from there actually over the disposal opening 26 should be disposed of. In this situation, the low pressure injector device allows it 58 in the collection container 24 lying, in itself still usable material when restarting the device 10 from the collection container 24 withdraw and re-supply the filtration aerosol layer. For this purpose, first the blower 50 turned on, so that the carrier fluid flow 54 formed. After that, the blower 40 turned on, so that is at the bottom of the collection container 24 loosens lying material and assumes a fluidized state in which it easily from the collection container 24 can be discharged. After that, the blower 60 switched on and in the collection container 24 befind Liche material over the line 66 fed to the filtration aerosol layer. The disposal opening 26 is closed. Once the collection container 24 emptied, the blower can 60 be turned off again and the device 10 operated as described above.

Alternative to the Niederdruckinjektoreinrichtung 58 could also be provided a vacuum conveyor to the in the collection container 24 lying material suck off and the raw gas stream 44 Add upstream of the housing or directly into the raw gas space 15 near the raw gas inlet 16 to promote. As a further alternative, the promotion could be fluidized with pressure, z. B. using a solid membrane pump.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4211465 C2 [0004]
• DE 19715195 A1 [0004]
• - DE 19924130 A1 [0005]
• - DE 10361266 A1 [0005]

Claims (29)

Filter device ( 10 ) for the purification of foreign bodies entraining gas, comprising: - at least one filter unit ( 12 ) having at least one filter surface on a raw gas side, the crude gas stream containing a foreign body ( 44 ), wherein the crude gas stream ( 44 ) and / or the filter surface filtration aids are fed and wherein attached to the filter surface filtration aids and / or foreign substances are cleaned; and a fluid bed arrangement ( 55 ) in which a carrier fluid stream ( 54 ), such that cleaned filtration auxiliaries and / or foreign substances at least partly as filtration aerosol in an environment of the filter unit ( 12 ) and / or can re-attach to a filter surface. Filter device ( 10 ) according to claim 1, wherein the fluid bed arrangement ( 55 ) in operation forms a filtration aerosol layer which extends in the vertical direction from a lower limit approximately at the level or slightly below the underside of the filter unit ( 12 ) up to an upper limit approximately at or just above the top of the filter unit ( 12 ). Filter device ( 10 ) according to claim 2, wherein the filtration aerosol layer extends down to 90 cm, preferably up to 60 cm and most preferably up to 50 cm below the bottom of the filter unit. Filter device ( 10 ) according to any one of claims 1 to 3, wherein in the carrier fluid stream ( 54 ) contained on the raw gas side gas is contained. Filter device ( 10 ) according to any one of claims 1 to 4, wherein the carrier fluid stream ( 54 ) the crude gas stream ( 44 ) contains itself. Filter device ( 10 ) according to one of claims 1 to 5, further comprising a swirling arrangement, by which on the raw gas side in the environment filter unit ( 12 ), in particular in the filtration aerosol layer, turbulence can be generated. Filter device ( 10 ) according to one of claims 1 to 6, further comprising a carrier fluid introduction arrangement ( 46 . 48 . 50 . 52 ), by which on the raw gas side of the filter unit ( 14 ) the carrier fluid stream ( 54 ) is producible. Filter device ( 10 ) according to claim 6 or 7, wherein the swirling / carrier fluid introduction arrangement ( 46 . 48 . 50 . 52 ) works continuously during operation. Filtering device according to claim 6 or 7, wherein the swirling / carrier fluid introduction arrangement ( 46 . 48 . 50 . 52 ) is controllable such that particles exceeding a predetermined mass density are no longer levitated and fall out of the filtration aerosol layer. Filter device according to one of claims 6 to 9, wherein the swirling / carrier fluid introduction arrangement ( 46 . 48 . 50 . 52 ) a arranged below the filter unit ring line ( 46 ), which with at least one - preferably a plurality - nozzles ( 52a . 52b . 52c . 52d ) having nozzle arrangement ( 52 ), the ring line ( 46 ) can be acted upon during operation with carrier fluid, such that in operation downstream of the nozzle arrangement ( 52 ) to the filter unit ( 12 ) and counteracting the gravitational carrier fluid flow ( 54 ) trains. Filter device according to one of claims 1 to 10, further comprising at least one raw gas space ( 15 ), the raw gas side of the filter unit ( 12 ), defining housing ( 18 ) with at least one in the raw gas space ( 15 ) opening raw gas inlet ( 16 ). Filter device ( 10 ) according to claim 11, wherein the crude gas inflow opening ( 16 ) at about level or slightly below the filter unit ( 12 ) is arranged. Filter device ( 10 ) according to claim 11 or 12, wherein the housing ( 18 ) at least one further into the raw gas space ( 15 ) opening inflow opening ( 20 ), can be fed through the filtration aids. Filter device ( 10 ) according to one of claims 7 to 13, wherein the crude gas stream ( 44 ), preferably at an angle of about 90 degrees, into the carrier fluid stream ( 54 ) opens. Filter device ( 10 ) according to one of claims 7 to 14, wherein the crude gas stream ( 44 ) below the filter unit ( 14 ) into the carrier fluid stream ( 54 ) opens. Filter device ( 10 ) according to any one of claims 1 to 15, further comprising a collecting tank associated with the raw gas side ( 24 ) for non-reusable particles. Filter device ( 10 ) according to claim 16, wherein the collecting container ( 24 ) at a lowest point a disposal opening ( 26 ), through the material from the collecting container ( 24 ) is removable. Filter device ( 10 ) according to claim 16 or 17, wherein the collecting container ( 24 ) below one below the filter unit ( 12 ) arranged and substantially funnel-shaped area ( 18b ) of the housing ( 18 ) is arranged. Filter device ( 10 ) according to one of claims 16 to 18, wherein the collecting container ( 24 ) a fluidizing arrangement ( 36 . 38 . 40 ) through which in the collecting container ( 24 ) befindliches material is acted upon with gas, which maintains its flowability. Filter device ( 10 ) according to one of claims 1 to 19, further comprising a conveyor ( 58 ), through which material from the collecting container ( 24 ) of the filtration aerosol layer and / or the crude gas stream ( 44 ) upstream of the filter unit ( 14 ) can be fed. Filter device ( 10 ) according to one of claims 1 to 20, wherein the cleaning device has a compressed air cleaning unit, which above the filter unit ( 12 ) is arranged on the clean gas side such that the filter unit ( 12 ) can be acted upon with compressed air in countercurrent flow in order to 12 ) to deposit deposited material on the raw gas side. Filter device ( 10 ) according to one of claims 1 to 21, wherein the filter unit ( 12 ) at least one filter element ( 12 ), which is designed as a rigid body filter. Filter device ( 10 ) according to claim 22, wherein the filter element ( 12 ) comprises a base body of sintered material, in particular containing sintered polyethylene particles as a main component, and wherein the base body is provided with a surface coating containing polytetrafluoroethylene particles. Filter device ( 10 ) according to claim 22, wherein the filter element ( 12 ) is formed from an array of polyethylene tubes, wherein on the polyethylene tubes in each case a filter membrane of polytetrafluoroethylene is laminated. Filter device ( 10 ) according to one of claims 11 to 24, wherein the housing ( 18 ) has at least one lateral and by a corresponding lid closable housing opening, which at the level of the filter unit ( 12 ) and through which the filter elements ( 14 ) can be used. Filter device ( 10 ) according to any one of claims 1 to 25, wherein the filtration aids are selected from the group comprising rock meal and other mineral dusts. Filter device ( 10 ) according to one of claims 1 to 26, wherein the filter unit ( 10 ) is arranged upstream - preferably a washing system or a cyclone separator - Vorabscheidestufe. Filter device ( 10 ) according to one of claims 1 to 27, wherein the filter unit ( 10 ) - a further filter stage is arranged downstream - preferably comprising a memory filter. Filter device ( 10 ) according to one of claims 1 to 28, wherein the filter device ( 10 ) is formed in a device for cleaning of sticky and / or tarry foreign substances containing exhaust air, in particular in a device of one of the following types can be installed: - device for the removal of air pollution in a wet painting plant, - device for the removal of air pollution in a dry paint plant, - Apparatus for the removal of air pollutants in a laser welding machine or other welding smoke suction system, - device for the removal of impurities in flue gases, in particular in flue gases, which occur in combustion processes; - apparatus for the removal of air pollutants in a cavity sealing facility, - apparatus for the removal of air pollutants in a plant for the bonding of metal parts; - Device for the removal of gaseous impurities in an exhaust gas stream with the addition of chemisorptive Filtrationshilfsstof fen, which react chemically with the gaseous impurities.