DE1113119B - Silencer for flowing and preferably also hot gases - Google Patents

Description

Silencer for flowing and preferably also hot gases The invention relates to a silencer for flowing and preferably also hot gases, in particular for pulsating flowing gases, such as exhaust gas from internal combustion engines.

The main field of application of the invention is the soundproofing of Exhaust gases of this type and from air currents, such as those generated by compressed air or processing devices occur, or even of uniform flows, such as the from turbines, e.g. B. in large power plants, escaping steam flows. In individual cases the invention is also used on the intake side of internal combustion engines in question.

For all these cases, the invention is based on gas supply systems that are already known for intermittently flowing gas streams in which a sheep-dampening unit of Plant from one system or from several connected in parallel and / or in series Systems of ducts of different lengths, in which the one in the sound-absorbing Unit entering gas flow is divided into partial flows, which are up to their reunification traverse different routes, and where preferably the ends of the Partial channels in a common flat or otherwise shaped surface more or open less flush and next to each other.

Preferably, the invention is based on already known such a gas guide systems in which the channels of a channel system or each channel system in such a way - calculated on average over the length of the sub-channel, or at least at the entry of the partial gas stream in a part of channel and / or at the exit of the partial gas stream from a sub-channel - have different free cross-sections, in such a way that the longer sub-channels each have a larger free cross-section than the shorter sub-channels until they merge at the named ends, d. H. that the mean free cross section of each of these sub-channels from channel to channel with the channel length - z. B. approximately proportional to this - increases.

In particular, the invention is based on gas supply systems of this type which are already known from where the total gas flow that comes from the partial gas flows at the ends of the partial channels is formed, is narrowed to a total cross-section which is much smaller is than that formed from the sum of the inlet cross-sections of the individual sub-channels Total entry cross-section into the sewer system.

Finally, the invention is based on already known such gas routing systems in which the after flowing through the channel system or several parallel and / or one behind the other connected channel systems through a narrowed outlet cross-section, z. B. the muffler housing or a connected pipe, or otherwise exiting total gas flow enters a further muffler unit, which has an empty space, d. H. a Helmholtz resonator may form, causing further acoustic attenuation of a pulsating occurred total gas flow, namely in the upstream silencer unit - that operates substantially with interference - not sufficiently attenuated frequencies. In known gas routing systems of this type, among other things, the further silencer unit is built into the silencer housing accommodating the channel systems and is connected in one piece to the channel system unit by common walls.

In summary, in its preferred embodiment, the invention is based on a gas routing system described in the German Auslegeschrift 1001053, which contains a so-called pressure transducer, and it can also have the other features and properties of the gas routing system described in this Auslegeschrift and also those in the German Auslegeschriften 1019 508, 1019 509 and 1 020 214 as well as those of the gas routing systems described in the German utility model 1736 379 , whereby only at least one duct system of the type mentioned must be present in each case.

In the aforementioned, already known designs of gas routing systems, all sub-channels of a channel system or each channel system lie next to one another essentially over their entire length, partition to partition, even if the channels, as usual, are curved; d. In other words, the direction of the gas flow emerging from the individual sub-channels does not run in the opposite direction to the direction of flow when entering the sub-channels, if each individual sub-channel is considered. Only the common direction of flow of the total gas flow of all sub-channels experiences a deflection of z. B. 901 or more with respect to the direction of entry, but at each point of each individual sub-channel, the flow generally runs essentially parallel to that of the adjacent sub-channel.

This previous embodiment makes difficulties when for the duct system or for the whole silencer unit or for several assembled Units a material should be used that is opposed to the high temperature of the incoming gas stream is sensitive to heat, at least after prolonged use or then reacts sensitively to heat when the acted upon sub-channel is caused by others Channels is separated from the cooled outer wall of the muffler housing.

The invention now assumes that preferably such heat-sensitive or materials sensitive to corrosion are used at elevated temperatures should, such as light metal, especially aluminum or aluminum alloys, or reasonably temperature-resistant plastics. The preferred use of such materials is not only recommended for reasons of the physical properties of these materials, but mainly for production reasons, because the production is then as Metalldruckg ., uä, -injection molding or -formguß possible or can be simplified in the form of one-piece Synthetic resin injection molded parts, cast parts or molded parts. This leads to smooth Inner walls that do not get dirty even with prolonged use, but of course a synthetic resin that is still heat-resistant at the maximum temperatures that occur use is.

The use of light metal in the form of cast or pressed pieces is in the case of an exhaust silencer composed of two spiral ducts connected in parallel already known. In these known designs, however, even in the application of die-cast aluminum, the inlet temperature of the hot gas, especially the exhaust gas of internal combustion engines, be too high to damage them in the long term To avoid duct partitions that are not on the outside, e.g. B. not on the refrigerated Housing outer wall, lie. Also, it is in terms of sound attenuation in the muffler and also undesirable with regard to the performance of the upstream motor that the Exhaust gas cools the channel system in the individual substreams very differently leaves.

The invention provides a remedy in the aforementioned cases, that one begins at the entry of a sub-channel or several or all sub-channels Entry canal route next to one at the end of the same entry canal segment and / or the outlet channel section beginning the inlet channel section of another sub-channel and has a partition in common with this or these, which in the case of the The flow of hot gases from the outlet duct section is cooled. Through this the temperatures on the inlet duct sections exceed the warr strength limit avoided, and it also results in a particularly simple and compact Structure for the arrangement of the sub-channels, which is also advantageous with cool gases.

These are neither aimed for nor achieved to a significant extent advantageous effects in an already known, provided with only one gas channel Exhaust muffler, in which the exhaust gas flow inside the muffler housing meets a spiral sheet metal wall and after the deflection of the gas flow through this sheet metal wall and through a second spiral sheet metal wall in the opposite direction is essentially perpendicular to the direction of entry laterally The outlet channel section leading out of the housing is formed inside This is because the section of the housing lying part of the path is not cooled by an outer wall of the housing and can therefore not contribute anything to the cooling of the inlet channel section.

The invention now makes this known for a single channel Channel routing for at least one channel system with several sub-channels use and it achieves the aforementioned advantageous effects and thereby creates the possibility of removing the duct system or duct systems even with hot exhaust gases Manufacture die-cast aluminum without damaging the duct walls.

In a preferred practical embodiment of the aforementioned basic idea of the invention is a sub-channel or are several or all sub-channels each for at the end of the inlet channel section from the inflow direction of the channel in the essentially deflected in the opposite direction and are those in this opposite direction running outlet duct sections of the individual sub-ducts from the preceding one Entry duct section of the individual sub-ducts through the for both duct sections a sub-channel common partition separated.

The cooling heat drain goes naturally in the channel system from the inside to the outside to the outer housing wall, which is cooled by the outside air or otherwise of the silencer.

This type of ducting is also used in an exhaust silencer known, in which the exhaust gas flow in two equal lengths, along the housing wall ., running sub-channels is divided, the gas streams of which are recombined several times and in the opposite direction by means of shorter partial channel pairs located further inside diverted and finally reunited in a common outlet channel are. But even in this case, the duct sections further inside cannot do anything contribute to the cooling of the two external duct sections.

If now, in the aforementioned embodiment of the invention, the gas with high temperature in the externally cooled housing outer wall at the If the next lying sub-channel occurs, the partial gas flow is not only already experienced a cooling when flowing along the cooled outer wall until it reaches the next one and channel section diverted in the opposite direction occurs according to the invention. He can then also share this second section with the first section Partition to a lower temperature than the inlet temperature of the partial gas flow to cool off. As a result, the partial gas flow is on the previous hot section cooled even more, and there is an overall also with regard to the occurring thermal stresses and other occurring with uneven heat distribution Effects desired equalization of the temperature and the heat gradient within of the muffler housing. According to the invention, this principle can now be continued for everyone inward sub-channel with a similar effect can be applied by each is deflected for itself in the opposite direction.

If the individual sub-channels are now located at right angles to their main flow and their counterflow direction, between the two outer lateral ones Housing walls of the silencer next to each other, then the inlet duct section is not but the outlet duct section of the shortest duct on the one cooled duct outer housing wall. In this case it is especially important to use similar beneficial ones Effects as in the case explained above through the inlet channel section Heat dissipation to the downstream outlet channel section according to the invention to cool the common partition through, with this opposite route from the heat is discharged directly to the outer wall. This arrangement is especially with a short sub-canal of particular importance, its first sub-section because of its shorter length than that of the other sub-channels anyway only shorter Offers opportunities to cool off. It is therefore useful to follow the sub-channels to be chosen so that both the first leg of a longer, preferably des longest sub-canal as well as the second or last sub-section of a shorter, preferably the shortest sub-channel of a channel system on the cooled outer wall of the muffler housing runs along in the aforementioned, known manner.

The described advantages of the invention result to a particular extent in the case of sub-sections of sub-channels arranged directly next to one another in this way Length, because then the previous section through which the hotter gas flowed shorter sub-channel of a section of an adjacent section through which cooler gas flows longer canal only through one of these two sections common to and from the the latter cooled partition is separated. The countercurrent cooling principle according to the invention is then not only for the opposing routes of each individual sub-channel for but also for the sub-channels among themselves and jointly.

For the practice of the invention, it is recommended that the outlet opening of each sub-channel transversely to the one given in its sub-sections Direction of flow lies and in each case in a discharge channel common to all sub-channels opens, which then essentially parallel to the channel system to the outlet opening from the muffler housing or preferably to an outlet nozzle with a narrowed Flow cross-section leads to which, as usual, another silencer unit of the same type or preferably in the manner of a Hehnholtz resonator or a can connect essentially empty space.

This design makes it particularly easy to use within a common silencer housing a second, the first channel system in itself known way parallel channel system of the same or similar design on the opposite side of a single outlet channel, i.e. also into the one the outlet openings of the second channel system open in the aforementioned direction, to be attached in the manner already mentioned at the beginning as known per se.

Because the adjoining empty space serving as the second downstream unit or the subsequent resonance muffler unit has a larger volume and therefore expediently also a larger free cross-section than the outlet channel of the upstream Should have pressure transducer unit, both units can advantageously be space-saving Way and simple manufacturing technology in an approximately cuboid, elongated outer housing accommodate that with the two duct systems and with the second downstream Unit has common outer walls and as a one-piece handy cast or molded piece manufacturbai is.

For this choice of material and for the cuboid design of the housing independent patent protection is not claimed.

If necessary, the axial outlet nozzle or the The outlet nozzle of the elongated cuboid structure easily has a second such Flange the silencer to one another with the parallel walls of the parallelepiped or otherwise connect, because the inlet opening of one of the channel systems upstream Entrance space as well as the outlet opening of the silencer in one of the is arranged perpendicular to the longitudinal direction of the cuboid boundary walls and penetrates them in the axial longitudinal direction. The inlet opening can also the same size as the outlet opening of the connected additional silencer unit to have.

In the drawing, a preferred embodiment of the invention is for example. illustrated, and that Fig. 1 shows a schematic view of a bottom view of one of two units assembled into one piece muffler, wherein the connecting piece of the base is omitted, Fig. 2 is a plan view of the top of the muffler of FIG. 1 at omitted cover plate and Fig Figure 3 is a cross-section along line 111-111 of Figure 2 through the one channel system, i.e. H. through one half of the muffler, while the other half is shown in the view; both halves are seen in the direction of the arrow indicated at section line III-111.

The z. B. from a motor vehicle engine or from a stationary engine exhaust gas stream is the inlet 1 of the silencer designated as a whole with 2 through an interposed exhaust pipe or directly through a connecting piece or via an upstream muffler, z. B. supplied via a silencer designed according to the invention. The inlet 1 may also have another shape have as drawn and breaks the of Fig. 3 with a connecting flange or connecting edge 4 provided as a whole with 5 designated end wall with the saw in the direction of flow vomliegenden part of the side walls 6 and 7 of the muffler forms an inlet space 3 which extends over the entire cross section of the muffler. The transverse wall 8 , seen in the flow direction, contains, according to FIGS. 1, 2 and 3, adjacent inlet openings 9, 10 and 11 of the inlet channel sections 12a, 13a and 14a of the channel system adjacent to the end wall 5. The section 12a is formed according to FIGS. 2 and 3 by the outer wall 6 and by a partition 15, which initially runs essentially parallel to the outer wall 6 , and opens into a transition space 16 which extends against the rear part of the silencer by a transverse wall 17 and is blocked off from the axially lying central part of the muffler by an inclined wall 18. In the space 16 , the partial gas flow from the inlet channel section 12a is deflected into a counter-rotating outlet channel section 12b which runs along the partition 15. The partial gas flow here thus goes in the opposite direction to the inlet direction, namely up to an outlet slot 19, which breaks through the inclined wall 18 delimiting the outlet duct section 12b towards the middle part of the silencer, perpendicular to the flow direction of the outlet duct section 12b. Thereafter, this partial "asstrom 0 flows into the central space 20 according to FIG. 3 , which extends in the axial direction, is closed off towards the front by the transverse wall 8 and towards the rear the transverse wall 17 either with its full cross section or with one of these Cross-section strongly narrowed, in Fig. 3 dash-dotted line at 34 indicated outlet nozzle which can be attached to an intermediate plate which can be screwed onto a pair of eyes 21 but is not shown in the drawings.

Inwardly, the outlet duct section 12 b of the first sub-duct 12 a, 1.2 b is delimited by a partition 22 which initially runs axially and then turns towards the side wall 7. This partition wall 22 forms with the next and extending also substantially in the longitudinal direction, but shorter partition 23 and with the oblique wall 18 the inlet duct 13 a leg of the next following shorter part of the channel 13 a, 13 b. Like the wall 22, this bends in the opposite direction to the inlet flow direction, that is to say in the opposite outlet channel section 13 b , which is formed by the next-following partition 24 and the inclined wall 18 . The outlet channel leg 13 b opens into an outlet slot 25 which penetrates the inclined wall 18 and the part flow perpendicular to its flow direction in the center space 20 can occur.

In the same way, the dividing wall 24 bent at the rear end with a further dividing wall 26 and the inclined wall 18 forms the inlet duct section 14a of the shortest sub-duct 14a, 14b, which, like the dividing wall 24, bends in the opposite direction into an outlet duct section 14b that extends from the housing outer wall 7, the partition wall 26 and the inclined wall 18 is formed. The outlet channel section 14 b opens through a slot 27 which breaks through the inclined wall 18 and allows the partial flow perpendicular to its flow direction to enter the outlet channel 20 which forms the central space.

As can be seen, the inlet and outlet duct sections 12a and 12b, 13a and 13b and 14a and 14b have greatly decreasing lengths compared to each other, calculated for the total length of the respective sub-duct, but they also have greatly decreasing lengths in relation to these lengths free passage cross sections, this especially because of the inclined position of the wall 18, as is apparent from 3 of FIG..

In the embodiment shown, the flow cross-sections of section 12a measured at section line III-III relate to section 12 b, section 13 a, section 13 b, section 14 a and section 14 b as 7,8- . 8: 5.3: 5.4: 3.4: 3.5. These cross-sectional ratios take into account the lower flow resistance in the case of the shorter sub-channels in the sense of the earlier proposals of the inventor mentioned at the beginning. The cross sections of the outlet slots 19, 25 and 27 decrease in the same sequence and approximately in the same ratio.

The channel system described above is shown in Fig. 2 and the lower part of FIG. 3. From the context of Fig. 1 and 2 shows that an identically designed second channel system is present in mirror image to the center line of FIG. 3. In FIG. 1 , the same reference numerals as in FIGS. 2 and 3 have therefore been used for the walls of the sub-channels. In Fig. 1 , in order to get a view of the wall 8 on the right front half, the end-side connecting flange 29 of the muffler housing is omitted on the right. The connecting flange 29 is screwed onto the wall 8 in an easily replaceable manner, and it can have a small central opening 30 which, bypassing the sub-channels described above, opens directly into the central collecting and outlet channel 20 and has a significantly smaller cross-section than the narrowest and shortest outlet channel section 14 b and 27 has its outlet slot. The opening 30 thus forms a two-channel systems common shortest and narrowest part channel whose cross-section be chosen larger or smaller as required by replacing the connecting flange 29 or may be omitted entirely.

In the upper half, FIG. 3 shows the opening 28 with the connection flange 29 removed by omitting the foremost end wall 5 of the silencer.

The preceding part of the description of an exemplary embodiment of the invention describes this essentially completely, i. That is, an invention is already seen in the duct design described for itself and also in the overall arrangement of the two duct systems to the central part, regardless of whether this structure is a silencer in itself or according to a first silencer unit in a one-piece connection with forms a downstream second silencer unit. This one-piece connection of two silencer units, which is already known in silencers, is particularly expedient and, above all, brings advantages in the structural design with regard to further simplification of manufacture.

In the example shown in FIGS. 1 and 2, the downstream second unit consists of an empty space 31 which is formed by the transverse wall 17, by extensions of the side walls 6 and 7 and by an end wall 32 . The outlet collecting channel 20 can open into the empty space 31 either with its full triangular cross section according to FIG. 3 or via the narrowed cross section of the outlet nozzle 34 (the cross section of which is substantially smaller than the sum of the inlet cross sections 9, 10 and 11).

The full triangular cross section according to FIG. 3 can also be present as an exit cross section 33 in the end wall 32 . Preferably, however, the outlet cross-section 33 is closed with a flanged cover plate which has an outlet opening whose cross-section is narrower than or equal to that of the nozzle 34. By removing the cover plate, not shown in the figures, there is the possibility of adding another silencer or another silencer unit, e.g. B. the inlet opening 1 of a further unit according to the invention, n-means of an intermediate pipe section either directly to the outlet collecting duct 20 or the nozzle 34 or directly to the end wall 32 without an intermediate pipe. In the latter case, the cover plate is provided with an outlet opening that corresponds as closely as possible to the inlet opening to be connected to the next unit. This opening or the opening 33 and / or the mouth of the collecting channel 20 or the nozzle 34 can also protrude into the empty space 31, extended with pipes and offset from one another. In any case, the empty space 31 in the exemplary embodiment forms a Helmholtz resonance damping chamber for the frequencies of the pulsating gas flow, which are not sufficiently damped in the upstream unit and depend on the speed of the motor.

The above-described thermal conditions in the channel system will be readily apparent from consideration of FIGS. 1 and 2. The entering the inlet channel leg 1.2a hot gas stream cools to the outer wall 6 in the course of its path to the chamber 16 from. The partial flow, which is already cooled as it flows over into the outlet channel section 12b , also keeps the dividing wall 15 common to the two sections correspondingly cool and also pre-cools the dividing wall 22. The partial flow entering the inlet duct section 13 a cools down accordingly until it is deflected into the outlet duct section 13 b , keeps the partition 23 common to the two sections 13 a and 13 b cool and pre-cools the partition 24.

The partial flow entering the inlet duct leg 14a is thereby cooled so that the partition wall 27 that separates it from the opposing part stream 14b is cooled by this, which in turn cools the side wall 7 out. Overall, the temperatures in the individual sub-channels and between the sub-sections of a sub-channel occur, in particular with the advantageous effect that the hotter and possibly harmful to the material inlet flow is cooled more than would be the case without the measures of the invention. - The invention has been described above for the case of hot gas flows, whether they are pulsating or not. The structural advantages of the mirror-symmetrical arrangement of the channel systems and the inventive arrangement of the sub-channels as well as the arrangement of the channel systems to form a common central channel and the possibly one-piece design of the channel system unit with a downstream second unit in a preferably one-piece molded or cast housing also apply to cool gas flows and thus in particular also in the case of an intake silencer. The invention is therefore not limited to hot gas flows and also not to exhaust silencers. The embodiment of the inventive concept is described above, for example, for a specific flow direction, as it is derived from the terms "inlet opening", "inlet chamber", "inlet duct section", "outlet duct section", " Outlet slit "," outlet manifold "," outlet nozzle "etc. emerges. As can be seen, however, the basic idea of the invention is not limited to the flow direction described, but the muffler can also be installed in the reverse direction in the gas flow, regardless of whether it consists of only one duct system or several duct systems or additionally from a wide muffler unit or from several further SchaRdämpfereinheiten, such as Helmholtz resonators, exists. The collecting duct 20 then becomes an entry duct for the duct system or for the duct systems connected to it. The slots 19, 24 and 27 then become entry slots, the sections 12 b, 13 b, 14 b become entry channel sections and the sections 12a, 13a, 14a become exit channel sections. The opening 1 and, if present, also the opening 30 then become outlet openings, and the space 3 becomes an outlet space. Overall, the terms used in the illustrated embodiment with regard to inlet and outlet are then reversed, with the flow directions reversing in the channels, but the structural advantages of the arrangement of the sub-channels and the channel systems for cool gas flows, in particular for an intake silencer, are retained. At the opening 1 , an outlet pipe can then be flanged on or a connecting pipe can lead to a resonance chamber or to another additional silencer unit. Irrespective of this reversal of the direction of flow, it has proven to be advantageous to connect the chamber 31, which previously acted as a resonator, to the collecting duct 20, which then acts as the inlet duct for the duct system, as an inlet space, whereby a narrowing intermediate nozzle may or may not be provided at the inlet of the collecting duct 20 . However, this upstream connection is not absolutely necessary, and the inlet channel 20 can also be flanged directly to the exhaust pipe of an internal combustion engine with a flange plate or the like or can form the air inlet of an intake silencer. It is particularly advantageous to two complete systems consist of two units, as shown for example in FIGS. 1 to 3, in such a manner preferably as Abgassehalldämpfergruppen, one behind the other switch, that the opening 1 of the outlet opening of the first system directly to the opening 1 of the second system is connected as its inlet opening, the first system preferably being provided with an upstream empty space 31 or a resonance silencer unit and the second system being provided with a downstream such unit.

For the parallel connection of several systems when using only one inlet 1 or 33 or 20 and / or only one outlet 1 or 33 or 20, the room 3 or 31 or 20 can be provided with lateral openings in the corresponding boundary walls 7 or 6 or with in FIGS. 1 and 2, not shown, screw-on and replaceable cover plates of the duct systems, which lead into the corresponding neighboring space of the system to be connected in parallel, so that both systems can rest against each other wall to wall and together require only one inlet pipe and only one outlet pipe.

Claims (2)

PATENT CLAIMS. 1. Silencer for flowing and preferably also hot gases, in particular for the exhaust gas from internal combustion engines, with one system or with several systems of channels, preferably of different lengths, in which the gas flow entering the silencer is divided into partial flows, preferably the mean free cross-section of each of these sub-channels increases with the channel length from channel to channel, characterized in that an inlet channel section (12a, 13a, 14a) beginning at the inlet of a sub-channel or several or all of the sub-channels next to one at the end of the same inlet channel section and / or the inlet channel section Another partial channel beginning outlet channel section (12 b, 13 b, 14 b) and with this or these has a partition (15, 23, 26; 22, 24) in common, which is cooled in the event of the flow of hot gases from the outlet channel section . 2. Silencer according to spoke 1, characterized in that a sub-channel or several or all sub-channels in each case for themselves at the end of the inlet channel section (12 a, 13 a, 14 a) is / are deflected from the inflow direction of the channel essentially in the opposite direction and that the outlet duct sections (12 b, 13 b, 14 b) of the individual sub-ducts running in this opposite direction are separated from the preceding inlet duct sections of the individual sub-ducts by the dividing wall (15, 23, 26) common to both duct sections of a sub-duct. 3. Silencer according to spoke 1 or 2, characterized in that the sections of different sub-channels, preferably of different lengths, are arranged side by side in such a way that the inlet channel section (13 a, 14 a) of the one, preferably shorter sub-channel C of, through which possibly hotter gas flows a throughflow of optionally cooler gas exit channel leg (12 b, 13 b) is separated of an adjacent other, preferably longer sub-channel only by a two subzones common and from the latter, preferably longer exit channel leg (12b, 13 b) cooled partition (22, 24) . 4. Silencer according to claim 2 or 3, characterized in that the inlet duct section (12a) of a longer, preferably the longest sub-duct and the outlet duct section (14 b) of a shorter, preferably the shortest sub-duct of a duct system in a manner known per se on each outer wall along the muffler housing. 5. Silencer according to one of claims 1 to 4, characterized in that the inlet openings (9, 10, 11) of the inlet duct sections (12 a, 13 a, 14 a) lie next to one another in a manner known per se in a surface preferably perpendicular to the flow direction and that the outlet openings (19, 25, 27) of the outlet channel sections (12b, 13b, 14b) lie next to one another in another surface (18) which is preferably inclined at an angle to the first surface. 6. Silencer according to one of claims 1 to 5 with two parallel-connected, fed from a common feed opening and opening into a common outlet channel channel systems, characterized in that the two * channel systems fed from a common inlet space with preferably each channel system adjoining inlet openings ( 9, 10, 11) are arranged on both sides of a common collecting duct (20) which runs essentially parallel to the two duct systems and serves as an outlet collecting space. 7. Silencer according to claim 6, characterized in that the two channel systems are designed to be mirror images of each other and are arranged in mirror image to the longitudinal center plane of the collecting chamber serving as the inlet or outlet plenum (20). 8. Silencer according to claim 6 or 7, characterized in that the inlet channel or outlet plenum serving as the collecting channel (20) has an approximately triangular and isosceles cross-section, the triangular base of which is formed by a side wall (7) of the silencer housing, and that the legs of the base to the tip for the successively increasing length in the same direction sub-channels (14 b and 14 a, 13 b and 13 a, 12 b and 12 a) form the inner walls of these sub-channels. 9. Silencer according to one of claims 1 to 8, characterized in that the partial gas flows of the outlet duct sections (12 b, 13 b, 14 b) perpendicular to their flow direction through outlet slots (19, 25, 27) into the collecting duct (20) serving as the outlet plenum. flow out. 10. Silencer according to claim 9, characterized in that the outlet slots (19, 25, 27) have from part channel to part channel in a manner known per se a free cross section which decreases in accordance with their length. 11. Silencer according to one of claims 1 to 10, characterized in that in a manner known per se, a further built-in silencer unit (31), for. B. a Hehnholtz resonator or an empty space, in one and the same housing in one piece with the channel system unit by common walls (6, 7, 17) is connected. 12. Silencer according to one of claims 1 to 11, characterized in that the silencer housing forms a cuboid body. 13. Silencer according to one of claims 1 to 12, that it is injection-molded, cast or pressed in one piece from light metal or synthetic resin. Considered pamphlets-. German Patent No. 649,253 ; German utility model No. 1736 379; Swiss patents No. 86 624, 127 360; French patent addendum No. 46,970 (addendum to patent No. 778,638); British Patent No. 275,437. U.S. Patent No. 129,065.