DE3732552A1 - Device for the removal of solid particles, especially soot particles, from the exhaust gas of internal combustion engines - Google Patents

Abstract

A device for the removal of solid particles, especially soot particles, from the exhaust gas of internal combustion engines has an electrostatic filter (10), through which the exhaust gas flows, with at least one filter tube (12) and a centrifugal separator (11), arranged on the outlet side, with a plurality of parallel-axis cyclones (21). For the manufacture of a series design type of compact construction which, without design modifications, is suitable for different power outputs of internal combustion engines, the cyclones (21), designed as tangential cyclones, are arranged around the electrostatic filter (10) in at least one group encompassing its circumference. The cyclone inlets (27) directly overlap radial openings (42) in the tube wall of the filter tube (12), whilst the cyclone outlets (28, 36) open into collecting chambers (30, 31, 37) arranged on the front faces of the cyclones (21). The device can be adapted to a different power output of the internal combustion engine by varying the diameter and length of the filter tube (12) and of the cyclones (21) and by omitting or adding individual cyclones (21) or a whole group of cyclones (21) (Fig. 1). <IMAGE>

Description

State of the art

The invention relates to a device for removing Solid particles, especially soot particles, from the exhaust gas of internal combustion engines, in particular of Diesel internal combustion engines, which in the preamble of the claim 1 defined genus.

Such devices must have the size and volume of the Engine power can be adjusted because of greater engine power there is also a larger amount of exhaust gas per unit time must be cleaned. This will be as compact as possible Construction aimed at low pressure loss.

In a known device of this type (DE-OS 35 00 373) shows the electrostatic precipitator, also electrostatic soot switch  called, two filter tubes running parallel to each other, so-called agglomerators. The centrifugal separator is in Axis direction immediately behind the electrostatic precipitator and consists of a total of eight axial cyclones. Four each of the axial cyclones aligned parallel to each other with a filter tube through an axial opening at the front Connection. At the end facing away from the axial openings of the axial cyclones are the first in two cross-sectional planes and second outlets arranged, the first outlets to discharge the particle-cleaned main exhaust gas as axially extending central dip tubes are formed, the on the one hand in the cyclone interior and on the other hand in one Protrude into the collecting space, and the second outlets to Removal of the particle-enriched exhaust gas bypass as Soot outlet openings are formed in the other Collection room. The axial cyclones are together with the two filter tubes in a common housing housed. To create a helical Direction of flow of the filter tubes axially into the Exhaust gas flowing in axial cyclones is immediately behind the axial openings each have an air guide in the form of a Baffle plate or a guide wing arranged.

In such a device the number is housable cyclones and limited by the diameter of the filter tubes. It can increase the amount of exhaust gas cannot be enlarged arbitrarily without at the same time Diameter of the filter tubes and that of the entire housing enlarge. The ratio of length to diameter of the Device is relatively large and therefore manufacturing technology unfavorable. The installation that hung on insulators Center electrode with spray disks inside the filter tubes to generate the electrostatic field is because of poor accessibility of the axial cyclones covered end faces of the filter tubes relatively difficult.

Advantages of the invention

The device according to the invention with the characteristic Features of claim 1 has the advantage over compact design to enable a series without design changes all engine performance. By arranging the cyclones around the at least one central filter tube around, can be a large number of Cyclones can be accommodated per group. In addition, by the division of the cyclones into two groups in the Axial distance from each other around the circumference of the filter tube are arranged, the number of cyclones that can still be accommodated be doubled. The ratio of length to diameter the device is much smaller and thus less expensive to manufacture.

By using tangential cyclones instead of known axial cyclones, on the one hand Particle separation improved and the other one axial length saved, which is due to the axial cyclones the required air baffle must be available. The Cyclones sit directly on the filter tube, and one a longer feed channel is unnecessary. Both ends of the Filter tubes are freely accessible, so that the assembly of the Center electrode with spray disks made considerably easier becomes.

The adaptation of the device according to the invention different engine power can be varied by Diameter and length of the filter tubes and cyclones, by omitting or adding individual cyclones or one whole group of cyclones or by one or two Filter tubes in parallel or in alignment in be achieved easily.  

By the measures listed in the other claims are advantageous developments and improvements in Claim 1 specified device possible.

By providing a baffle at each cyclone inlet the rotary flow of the exhaust gas flow in the Tangential cyclones improved.

By providing an electrostatic precipitator with a radial clearance surrounding housing shell arises between electrostatic precipitators and housing shell an annulus in which the tangential cyclones housed and in a structurally simple manner with The electrostatic filter and the casing can be connected. By radially extending transverse walls on the one hand front cover of the cyclones can be effected and others at the same time in a simple manner Collection rooms for the main and secondary exhaust gas flow realized will. To short between the output of the Avoiding filter tubes and the collecting rooms is the hollow cylindrical housing section of the cyclones in the area of Exhaust inlet with the pipe wall of at least one Filter tube connected gastight, e.g. welded.

If you want to avoid such an additional weld, so is according to a further embodiment of the invention between the housing jacket and the at least one filter tube to provide a transverse bulkhead that functions as a partition Has axial openings through which the hollow frustoconical housing section of the axial cyclones with part of its longitudinal extent, the axial opening sealing, put through. The transverse bulkhead is limited thereby directly the one collecting room.

By providing two groups of tangential cyclones,  which are arranged at an axial distance from each other, and by summarizing the facing sides of the Cyclones of the different groups are located in collecting rooms a common ring chamber with a disposal nozzle, will be a compact design of the device for high Engine power created. The common Annulus either the soot collector or the exhaust collector for form the cleaned main exhaust gas flow.

By axially overlapping the different groups associated tangential cyclones according to another Embodiment of the invention is extremely small axial length of the device achieved.

In a further embodiment of the invention, the Electrostatic precipitator consisting of two filter tubes closed at the ends, those with aligned tube axes at an axial distance from each other are arranged. Each filter tube carries close to theirs Radial openings to the end facing away from the tangential cyclones an inlet port for supplying exhaust gas with preferably tangential inflow direction. With this constructive The design remains due to the separate exhaust gas supply to the two filter tubes used in many commercial vehicle engines Get the usual dual flow exhaust system, so that the Need a prior summary with There is no pressure loss. There is also the possibility a central summary of the cleaned Exhaust main flow when according to another embodiment the invention lies between the two cyclone groups common ring chamber forms the exhaust gas collection chamber. Here becomes an extended agglomeration route in reached the filter tubes. Soot lines are for the Exhaust gas bypass exists twice, but they are in the To dimension diameter much smaller, which at cramped installation conditions can have advantages.

drawing

The invention is illustrated in the drawing Exemplary embodiments in the description below explained in more detail. Show it:

Fig. 1 is a longitudinal section of a device removal. For of solid particles from the exhaust gas of internal combustion engines according to the section line II in Figure 2,

Fig. 2 shows a section of the device according to line II-II in Fig. 1,

Fig. 3 shows a same view as in Fig. 2 of the device according to a second embodiment,

FIGS. 4 and 5 each show a longitudinal section of the device according to a third and fourth embodiment,

Fig. 6 shows a cross section along the line VI-VI in Fig. 5,

Fig. 7 shows a longitudinal section of the device according to a fifth embodiment.

Description of the embodiments

Schematically in Fig. 1 in longitudinal section and in Figure 2 device shown in cross section for removal of solid particles, in particular soot particles from the exhaust gas of an internal combustion engine, especially a diesel internal combustion engine, consisting. Of an electric filter 10, also known as electrostatic Rußweiche, and this downstream centrifugal separator 11 . In a known manner, the electrostatic filter 10 has a filter tube 12 , a so-called agglomerator or coagulator, which consists of a separator tube 14 connected to the positive pole of a high-voltage source 13 and a central electrode 15 with spray disks 16 connected to the negative pole of the high-voltage source 13 . The center electrode 15 is kept insulated in the separator tube 14 by means of two front-side insulators 17 , 18 .

The filter tube 12 is surrounded by a housing jacket 19 with a radial spacing, so that a cavity 20 with an annular cross section is formed between the outer wall of the filter tube 12 and the inner wall of the housing jacket 19 . In this cavity 20 , the centrifugal separator 11 is accommodated, which consists of a plurality of so-called cyclones 21 , which are arranged in two mutually axially spaced cyclone groups, so-called multiclones, in the cavity 20 directly adjoining one another and thus enclosing the circumference of the filter tube 12 . Each cyclone 21 has, in a known manner, a housing 22 with a hollow cylindrical housing section 23 and an adjoining hollow cone-shaped housing section 24 which tapers towards the free end. By two radially extending transverse walls 25, 26, the hollow cylindrical housing portions are closed 23 of the cyclone body 22 on the side facing away from the hollow truncated cone-shaped housing portion 24 front end. An inlet 27 , via which each cyclone 21 is connected to the filter tube 12 , and on the other hand an outlet 28 for a particle-cleaned main exhaust gas stream open into the hollow cylindrical housing section 23 . The outlet 28 is designed as a centrally arranged dip tube 29 which penetrates the transverse wall 25 or 26 and on the one hand into the hollow cylindrical housing section 23 of the cyclone housing 22 and on the other hand into an annular collecting space 30 or 31 which on the one hand projects from the transverse wall 25 or 26 and, on the other hand, is delimited by a cover 32 or 33 which closes the housing jacket 19 at the end. In the collecting spaces 30 , 31 , the largely particle-free exhaust gases emerging from the cyclones 21 as the core flow via the immersion tubes 29 are combined to form an exhaust gas main stream which is fed to the exhaust of the internal combustion engine via exhaust gas disposal connections 34 and 35, respectively. The smaller-diameter clear opening of the frustoconical housing section 24 of each cyclone housing 22 forms a second outlet 36 for the particles or soot particles migrating down the walls, which together with residual exhaust gases are combined to form a particle-enriched secondary exhaust gas stream that is significantly smaller than the main exhaust gas stream. The combination takes place in a common annular chamber 37 , in which the second outlets 36 of all cyclones 21 open and from which the particle-laden exhaust gas bypass is fed via a radial soot disposal nozzle 38 to a soot disposal device, not shown. The annular chamber 37 is delimited within the cavity 20 by the housing walls of the frustoconical housing sections 24 of the cyclone housing 22 . For this purpose, it is necessary that the cyclone housing 22 are gas-tightly connected on the one hand to the housing jacket 19 and on the other hand to the separator tube 14 of the filter tube 12 , for example by welding, so that there is no short circuit between the inlet 27 of the cyclones 21 and the annular chamber 37 . As an alternative, it is also possible for the annular chamber 37 by two in Fig. 1 by dashed lines 39 and 40 to limit drawn partition walls or bulkheads, the gas-tight with the inner wall of the housing shell 19 are connected. Each transverse bulkhead 39, 40 carries a number of axial openings 41 corresponding to the number of cyclones 21 , through which the hollow-section-shaped housing section 24 of a cyclone housing 22 protrudes with part of its longitudinal extent in a sealing manner. The cyclones 21 are thus held on the one hand in the transverse bulkheads 39 , 40 and on the other hand with their hollow cylindrical housing section 23 between the housing jacket 19 and the separator tube 14 of the filter tube 12 . The assembly of the cyclones 21 is simplified since they only have to be plugged in and there is no need to weld the hollow cylindrical housing section 23 to the separator tube 14 and housing jacket 19 .

As can be seen in particular from FIG. 2, the cyclone inlets 27 open tangentially into the interior of the cyclone and each cover a radial opening 42 in the wall of the separator tube 14 of the filter tube 12 . The radial openings 42 are each arranged near an end of the filter tube 12 which is closed by the transverse walls 25 and 26 and are evenly distributed over the circumference of the separator tube 14 . Their number corresponds in each case to the cyclones 21 surrounding the filter tube 12 in a group. In order to improve the tangential inflow of the exhaust gas from the filter tube 12 into the cyclones 21 , a baffle 43 is provided at the cyclone inlet 27 , which protrudes into the interior of the cyclone from the inlet edge remote from the housing. Each baffle 43 is cut out of the housing wall of the cyclone housing 22 and bent inwards.

The filter tube 12 has an inlet connection 44 through which the exhaust gas of the internal combustion engine is supplied. The inlet connector 44 is passed through the annular chamber 37 and opens tangentially in the middle of the separator tube 14 of the filter tube 12 . The immersion tubes 29 are made of perforated sheet metal for noise reduction in the area of the collecting spaces 30 , 31 , as is indicated for an immersion tube in FIG. 1.

The operation of those described above Exhaust gas purification device is as follows:

The exhaust gas coming from the diesel internal combustion engine is fed via the inlet connection 44 to the filter tube 12 , the so-called agglomerator. The exhaust gas flows through the filter tube 12 in a three-way flow from the center to both ends and is conducted there via the radial openings 42 into the cyclones 21 . When flowing through the electrostatic field prevailing in the filter tube 12 , the soot particles coagulate in a known manner to form larger agglomerates, which reach the cyclones with the exhaust gas stream and are mechanically separated there. The baffles 43 on the cyclone inlets 27 give the agglomerates a sufficiently high tangential speed and, due to the centrifugal force, are carried in the cyclones 21 to the wall of the cyclone housing 22 , where they travel spirally in the frustoconical housing section 24 to the second outlet 36 and there with them get part of the exhaust gas into the annular chamber 37 . The cleaned exhaust gas leaves the cyclones 21 as the core flow via the immersion tubes 29 and reaches the two annular collecting spaces 30 , 31 , in order then to be fed through the exhaust gas disposal connections 34 , 35 to the exhaust system of the internal combustion engine. The soot-laden waste gas secondary stream emerging from the soot collecting ring chamber 37 via the disposal connection 38 is only about 1% of the main exhaust gas stream leaving the collecting spaces 30 , 31 and is fed to a soot disposal system, which can be, for example, a simple collecting container or a soot combustion device.

All of the exemplary embodiments shown in the further figures the exhaust gas purification device operate in the above described way. They differ only in  constructive modifications, which are detailed below are explained.

In the illustrated only schematically in cross-section cleaning device according to FIG. 3, two parallel filter tubes 112, 112 'are provided which are directly adjacent to each other. The cyclones 21 are arranged in one or two groups. Each group of cyclones 21 encloses the two filter tubes 112 , 112 ', the cyclones 21 in turn directly abutting one another with their hollow cylindrical housing section 23 . Half of the cyclones 21 of a group is connected to the one filter tube 112 and the other half to the filter tube 112 ', in turn the inlets 27 of the cyclones 21 each having a radial opening 42 or 42 ' in the separator tube 114 or 114 'of Cover filter tubes 112 or 112 '. The housing jacket 119 surrounding the cyclones 21 has an elliptical cross section here. Moreover, the device is right of FIG. 3 in FIG. 1 and 2 coincide, so that like parts are designated by like reference numerals.

In the further exemplary embodiment of the cleaning device, which can be seen schematically in longitudinal section in FIG. 4, two groups of cyclones 21 are in turn grouped around a filter tube 12 , the hollow cylindrical housing sections 23 of the individual cyclones 21 of a group directly abutting one another, as shown in FIG. 2 but can also have a certain distance from each other. The axial spacing of the two cyclone groups is selected to be substantially smaller than twice the axial length of the frustoconical housing sections 24 , so that in the case of a circumferentially offset arrangement of the cyclones 21 belonging to each cyclone group, the frustoconical housing sections 24 of non-group cyclones 21 are located in the common annular chamber 37 for the Axially overlap soot collection. The inlet port 244 , which in turn opens centrally in the filter tube 12, is guided axially without a cyclone 21 in a cyclone group in the cavity 20 between the housing jacket 19 and the filter tube 12 and opens tangentially into the filter tube 12 via a bend 245 which extends through the annular chamber 37 . Otherwise, this embodiment of the cleaning device is unchanged from the embodiment in FIGS. 1 and 2. The identification of the other components identical to FIGS. 1 and 2 by reference numerals has therefore been dispensed with.

In the cleaning device to be seen schematically in FIG. 5 in longitudinal section and in FIG. 6 schematically in cross section according to a fourth exemplary embodiment, two filter tubes 312 and 312 ', which are closed at the ends, are arranged with aligned tube axes at an axial distance from one another. The two filter tubes 312 , 312 'are connected to each other with an axially aligned intermediate sleeve 346 , which, however, only serves to internally delimit the cavity 20 outside the area of the filter tubes 312 and 312 '. Each filter tube 312 , 312 'is assigned to a group of tangential cyclones 21 which directly enclose the separator tube 314 or 314 ' of the filter tube 312 or 312 'and - as can be seen in FIG. 6 - with their hollow cylindrical housing sections 23 directly against one another and rest against the separator tube 314 or 314 'and on the housing jacket 19 . The tangential cyclones 21 belonging to a group are in turn connected via inlets 27 and 27 ', which cover radial openings 342 and 342 ' in the separator tubes 314 and 314 ', to the inside of one of the filter tubes 312 and 312 '. The radial openings 342 and 342 'are in turn arranged at a short distance in front of a closed end wall of the filter tube 312 and 312 '. The inlet ports 344 and 344 'of the filter tubes 312 and 312 ' each open directly at the opposite closed end of the filter tube 312 and 312 'and are outside the housing shell 19th The exhaust gas is fed via the inlet connection 344 and 344 'of the filter tube 312 and 312 ' again with a tangential direction of flow.

As can also be seen in connection with FIG. 6, the hollow cylindrical housing sections 23 of the cyclones 21 in the inlet area are not welded to the wall of the separator tubes 314 or 314 ', as is the case in FIG. 1. Rather, -., As in the modification shown in Figure 1 by dashed lines - again annular transverse bulkheads 39 and 40 are provided, which limit the Rußsammel ring chamber 37 in the axial direction. These transverse bulkheads 39 , 40 have axial openings 41 , into which the cyclones 21 with their hollow truncated cone-shaped housing sections 24 are inserted. Only a small piece of the frustoconical housing sections 24 protrude into the annular chamber 37 . By spreading these projecting housing sections, the cyclones 21 are held in the transverse bulkheads 39 , 40 . The transverse bulkheads 39 , 40 represent separating plates which, together with the housing jacket 19 and the intermediate sleeve 246, close off the annular chamber 37 in a gas-tight manner. The remaining structure of the cleaning device described corresponds to that in FIGS. 1 and 2, so that the same components are provided with the same reference numerals.

The essential difference between the embodiment of the cleaning device which can be seen schematically in longitudinal section in FIG. 7 and the embodiment shown in FIGS . 5 and 6 is that the cyclones 21 of the two cyclone groups are reversed in their installation direction, so that they are formed by the immersion tubes 29 first outlets 28 open into the annular chamber 437 . To discharge the main exhaust gas flow to the exhaust system of the internal combustion engine, there is only an exhaust gas disposal connection 438 which radially extends from the annular chamber 437 . The second outlets 36 on the free ends of the frustoconical housing sections 24 of the cyclones 21 each open into an annular collecting space 430 or 431 . These are delimited on the one hand by the covers 32 and 33 closing the housing jacket 19 and on the other hand by annular transverse bulkheads 39 and 40 . As in the embodiment in FIG. 5, the transverse bulkheads 39 , 40 have axial openings 41 through which the frustoconical housing sections 24 protrude with a small part of their longitudinal extent. For the soot disposal of the collecting rooms 430 , 431 and the discharge of the exhaust gas bypass, each collecting room 430 or 431 is provided with a soot disposal connection 434 or 435 . This design change can be achieved with unchanged external dimensions of the device, a greater length of the filter tubes 312 and 312 'and thus an extended agglomeration distance. There are two soot lines for soot disposal, but they must be dimensioned very small, which can be advantageous in tight spaces. Otherwise, the device is identical to that in FIGS. 5 and 6, so that the other components have not been identified by reference numerals.

The device can due to its volume and in the multiple flow deflections that take place Main silencer of the exhaust system of an internal combustion engine replace and achieve the same or better sound absorbing Effects like conventional silencers.

Claims (16)

1.Device for removing solid particles, in particular soot particles, from the exhaust gas of internal combustion engines, in particular diesel internal combustion engines, with an electrostatic filter through which the exhaust gas flows, which has at least one filter tube with an electrostatic field, and with a downstream of the electrostatic filter in the exhaust gas stream, with this a unit combined centrifugal separator, which consists of a plurality of cyclones parallel to the at least one filter tube, which are each connected via an inlet to the at least one filter tube and have a first outlet for a particle-cleaned main exhaust gas stream and a second outlet for a particle-enriched exhaust gas secondary flow open into separate collection rooms, each provided with a disposal connection, characterized in that the cyclones ( 21 ) are arranged around the electrostatic filter ( 10 ) in at least one group enclosing its circumference , that the cyclones Clone inlets ( 27 ) open tangentially in the interior of the cyclone and cover radial openings ( 42 ) which are provided in the tube wall of the at least one filter tube ( 12 ) near a closed tube end distributed over the tube circumference, and that the collecting spaces ( 30 , 31 , 37 ) open in Axial directions opposite end faces of the cyclones ( 21 ) are arranged. 2. Device according to claim 1, characterized in that each cyclone (21) a housing (22) having a hollow-cylindrical in the region of the inlet (27), closed at one end face of housing portion (23) and an adjoining, to the free front end, has a tapered hollow truncated-cone-shaped housing section ( 24 ) and that the first outlet ( 28 ) from an immersion tube ( 29 ) which extends through the closed front end and protrudes centrally into the hollow-cylindrical housing section ( 23 ) and the second outlet ( 36 ) from the smaller-diameter clear opening of the hollow truncated-cone Housing section ( 24 ) is formed. 3. Apparatus according to claim 2, characterized in that a guide plate ( 43 ) is provided on each cyclone inlet ( 27 ), which protrudes into the interior of the cyclone from the inlet edge remote from the housing. 4. The device according to claim 3, characterized in that the guide plate ( 43 ) is cut out of the housing wall and bent outwards. 5. Device according to one of claims 1-4, characterized in that the electrostatic filter ( 10 ) is surrounded by a housing jacket ( 19 ) with an approximately the outer diameter of the hollow cylindrical housing section ( 23 ) of the cyclones ( 21 ) and the radial distance between them Cyclones ( 21 ) are held with their hollow cylindrical housing section ( 23 ) and that the front cover of the hollow cylindrical housing sections ( 23 ) is effected by a cover ( 32 , 33 ) connected to the housing jacket ( 19 ), which cover also serves as a collecting space ( 30 , 31 ) limited. 6. The device according to claim 5, characterized in that the hollow cylindrical housing portion ( 23 ) of the cyclones ( 21 ) at least in the region of the cyclone inlet ( 27 ) with the tube wall ( 14 ) of the at least one filter tube ( 12 ) gas-tightly connected, for example welded . 7. The device according to claim 5, characterized in that between the housing shell ( 19 ) and the at least one filter tube ( 12 ) at least one gas-tight separating plate ( 39 , 40 ) is held, which has axial openings ( 41 ) through which the Hollow frustoconical housing section ( 24 ) of the cyclones ( 21 ) with part of its longitudinal extent, sealingly protrudes through the axial opening ( 41 ), and that the at least one separating plate ( 39 , 40 ) delimits a collecting space ( 37 ; 430 , 431 ). 8. Device according to one of claims 1-7, characterized in that two groups of cyclones ( 21 ) are provided at an axial distance from one another and that the two mutually facing sides of the cyclones ( 21 ) of the different groups lying collection spaces to a common annular chamber ( 37 ; 437 ) are combined with a disposal nozzle ( 38 ; 438 ). 9. The device according to claim 8, characterized in that arranged that the associated a group of cyclones (21) offset in the circumferential direction with respect to that of the other group associated cyclones (21) and that the axial distance of the cyclone groups is selected such that the hollow truncated cone-shaped housing sections (24 ) non-group cyclones ( 21 ) overlap axially in the common annular chamber ( 37 ). 10. The device according to claim 8 or 9, characterized in that the at least one filter tube ( 12 ) is closed at the end and carries an inlet port ( 44 ) approximately in the middle for supplying exhaust gas with preferably tangential inflow direction. 11. The device according to claim 10, characterized in that the inlet connector ( 44 ) is guided through the common annular chamber ( 37 ). 12. The apparatus according to claim 10, characterized in that the inlet nozzle ( 244 ) without a cyclone ( 21 ) in a cyclone group axially between the electrostatic precipitator ( 10 ) and the housing jacket ( 19 ) and through a common annular chamber ( 37 ) extending elbow ( 245 ) opens into the at least one filter tube ( 12 ). 13. Device according to one of claims 1-12, characterized in that the electrostatic filter ( 10 ) has two parallel, adjacent filter tubes ( 112 ; 112 ') and that each half of the cyclones ( 21 ) in the at least one group with a filter tube ( 112 or 112 ') is connected. 14. The apparatus according to claim 8 or 9, characterized in that the electrostatic filter ( 10 ) has two filter tubes ( 312 ; 312 ') which are closed at the ends and which are arranged with aligned tube axes at an axial distance from one another, in each case that the cyclones ( 21 ) belonging to a group with one of the filter tubes ( 312 ; 312 ') are connected and that each filter tube ( 312 ; 312 ') near its end remote from the radial openings ( 342 ; 342 ') has an inlet port ( 344 ; 344 ') for supplying exhaust gas, preferably tangential Inflow direction carries. 15. The apparatus according to claim 14, characterized in that the two filter tubes ( 312 ; 312 ') protrude from the end of the housing shell ( 19 ) that the transverse to the longitudinal axis of the filter tubes ( 312 , 312 ') extending inlet connector ( 344 ; 344 ' ) are outside the casing ( 19 ). 16. The apparatus according to claim 14 or 15, characterized in that the first outlets ( 28 ) of the cyclones ( 21 ) open into the common annular chamber ( 437 ) lying between the two cyclone groups.