Abstract:
A road finisher with an internal combustion engine and an engine exhaust pipe has a muffler with an enlarged diameter with respect to that of the engine exhaust pipe, and a pipe for discharging emissions of a building material. The emissions pipe passes though the muffler mounted to the muffler without discharging into the muffler and the exhaust pipe output is supplied to the muffler interior and the muffler has a discharge pipe for the engine exhaust gases.

Description:
FIELD OF THE INVENTION 
   The invention relates to a road finisher of the type illustrated in the preamble of claim  1 . 
   BACKGROUND OF THE INVENTION 
   Such a road finisher is known from EP 843 044. The known road finisher is provided with a suction device which sucks off the emissions discharged by the building material, concentrates the same at one location and discharges them to the surrounding area where they do not annoy the operators and persons in the surrounding area. To this end, the known road finisher contains discharge channels that extend from the suction device upwards beyond the driver&#39;s seat and possibly beyond further work places for operators and discharge the emissions from this point to the air. Such an arrangement of discharge channels, however, has a relative complex construction as a plurality of fixing elements have to be provided to support the discharge channels safely from vibrations which means increased manufacture as well as assembly efforts. 
   From U.S. Pat. No. 6,832,872, an exhaust system for road finishers is known in which exhaust gases from the internal combustion engine and emissions from the building material are discharged via a common exhaust port. Upstream of the exhaust port, there is a mixing chamber where the sucked off emissions and the engine exhaust gases are mixed. The purpose of this arrangement is to change the magnitude of the exhaust pulses to achieve noise reduction. The mixing chamber, the engine exhaust pipe and the exhaust port essentially have the same diameter, so that here noise reduction is not achieved by an increase in diameter but by mixing in the emissions. 
   EP 666 373 describes a road finisher with a suction device for emissions of the building material, wherein the sucked off emissions are passed through an air cleaner which passes a portion of the emissions into the air intake pipe for the internal combustion engine. A further portion of the emissions is directly passed into the exhaust system of the internal combustion engine via a hose pipe downstream of the muffler and is discharged to the air together with the exhaust gas. However, this constructive solution is also discontenting as the hose is freely suspended in the air and can be vigorously moved, for example by the influence of wind, or requires the same complex fixing elements as already described above. 
   BRIEF DESCRIPTION OF THE INVENTION 
   The object underlying the invention is to simplify a road finisher with suction device as to the construction and with respect to the assembly efforts. 
   With the embodiment according to the invention, the muffler that is anyway present in the exhaust pipe and by usual means acts by an increase in diameter is simultaneously used as mounting for the emission pipe, which on the one hand drastically reduces the assembly efforts and on the other hand combines the two exhaust pipes to form one unit defining one single place of discharge. It has been surprisingly found that the passage of the emission pipe through the muffler does not reduce the efficacy of the muffler with respect to noise reduction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, one embodiment of the invention is illustrated more in detail with reference to the drawings. In the drawings: 
       FIG. 1  shows a schematic representation of a road finisher according to the invention, 
       FIG. 2  shows a perspective representation of a muffler designed according to the invention, 
       FIG. 3  shows the front view of  FIG. 2 , and 
       FIG. 4  shows the section IV-IV of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a schematic representation of an exemplified road finisher  1  which can be of any known construction. The meaning of the term “road finisher” is herein broad and the term relates to any road making machine driven by an internal combustion engine and processing building material that discharges emissions. 
   The road finisher  1  is designed for applying a bituminous or bitumen-containing surface cover onto a traffic area. The road finisher  1  comprises a chassis  2  running automotively, i.e. by means of an internal combustion engine  4 , on an undercarriage  3  (wheels or crawlers) into the direction of motion F (direction of fitting). The road finisher  1  contains a work place  5  for the driver and the facilities usually provided in road finishers, that means for example a bunker  6  for hot bituminous building material located in front of the work place  5  in the direction of motion F, and a building beam  7  which is trailed behind the work place  5  in the direction of motion F. The building material taken from the bunker  6  and transported to the rear in a manner not shown is placed in front of a building worm or another lateral distributor  8  and thereby uniformly distributed across the direction of motion F and placed in front of the building beam  7 . In particular in the area of the cross conveyor  8  it cannot be avoided that emissions of the hot building material, for example bitumen aerosols, reach the surrounding area. Although these emissions are not detrimental to health according to present knowledge they are annoying, in particular for operators exposed to them throughout the day. To this end, a suction device  9  for sucking in the emissions is provided. In the represented embodiment, the suction device  9  contains a first suction means  9   a  in the area of the cross conveyor  8 . The suction means  9   a  is preferably designed as cover  10  extending along the whole cross conveyor  8  and covering the same at least towards the top. The cover  10  collects the emissions and discharges them via an emission pipe  11 . The discharge of the emissions is preferably supported by a suck-and-blow aggregate  12  which can, for example, contain an electrically or hydraulically driven turbine. 
   In the represented embodiment, the suction device  9  contains a second suction means  9   b  which collects and removes the emissions possibly exiting from the bunker  6 . The second suction means  9   b  in turn contains a suction hood  13  preferably extending over the width of the bunker  6 , which sucks off the emissions and removes them via an emission pipe  14 , preferably again supported by a non-depicted suck-and-blow aggregate. 
   The two emission pipes  11  and  14  of the two suction means  9   a ,  9   b  are combined in a common emission pipe  15 . 
   The internal combustion engine  4 , for example a diesel generator, contains an exhaust system with an engine exhaust pipe  16  ending in one of the common mufflers (exhaust muffler)  17 . The muffler  17  has a sound absorbing effect by an increase in the diameter between the engine exhaust pipe  16  and the interior of the muffler  17 . 
   As is in particular represented in  FIGS. 2 to 4 , the muffler  17  contains a case  17   a  which can be cylindrical, cuboid-shaped or have any other cross-section. The case  17   a  is arranged with an essentially perpendicular centre line and closed by a lower cover  17   b  and an upper cover  17   c  to the top and bottom. In the represented embodiment, the covers  17   b  and  17   c  are designed as essentially circular disks and extend perpendicularly and transversely to the centre line of the case  17   a . The covers, however, can also have a conical or pyramidal or similar design and/or be integrally connected with the case and cause a closure of the muffler by bending. 
   The emission pipe  15  is designed as tube with a closed wall and an essentially constant cross-section and enters in the lower area of the muffler  17 , preferably by penetration of the lower cover  17   b , the interior of the muffler  17  enclosed by the case  17   a  and passes through the muffler  17  from the bottom to the top without flow communication with the interior of the muffler  17 . Subsequently, the emission pipe  15  exits again from the muffler  17  in the upper area, preferably by penetrating the upper cover  17   c . Above the muffler  17 , the emission pipe  15  is continued with an outlet area  15   a  ending in an outlet port  15   b.    
   The muffler  17  is designed as mounting for the emission pipe  15 , preferably the lower cover  17   b  and/or the upper cover  17   c  holding the emission pipe  15 . The mounting can be effected by penetration openings in the muffler  17  adapted to the dimensions of the outer periphery of the emission pipe  15 . Preferably, the emission pipe  15  is welded to the muffler  17  which is advantageously made in the area of the penetration openings, i.e. the lower and/or upper covers  17   b ,  17   c . By this mounting, no further fixing, for example by pipe clamps, connection webs, clamps or the like, are required in the area of the muffler  17  and the outlet area  15   a , as is shown in the figures. 
   The exhaust pipe  16  of the exhaust system also ends in the lower area of the muffler  17 . The exhaust pipe  16  can, as  FIG. 2  shows, be arranged diagonally to the centre line of the case  17   a  or, as shows  FIG. 3 , perpendicularly to the centre line of the case  17   a . The engine exhaust gases penetrate the muffler pot, expand whereby silencing is achieved, and exit from the muffler  17  in the upper area via an outlet area  16   a  ending in an exhaust port  16   b  without mixing with the emissions. The engine exhaust pipe  16  and its outlet area  16   a , too, are preferably welded to the muffler. 
   The emission pipe  15  and the engine exhaust pipe  16  in the area of the outlet area  16   a  are arranged in essentially parallel centre lines, wherein the centre lines of the pipes  15 ,  16   a  extend essentially in parallel to the centre line of the muffler  17 , and the centre lines of the emission pipe  15  are located in a common plane with the outlet area  15   a  of the outlet area  16   a  and the muffler  17 . As is in particular shown in  FIG. 1 , the outlet areas  15   a ,  16   a  are arranged one behind the other in the direction of motion F, so that the visual range of the ranged one behind the other in the direction of motion F, so that the visual range of the driver from the work place  5  is not affected by the second pipe  15  if the exhaust system is arranged diagonally laterally in front of the work place  5 . Moreover, the muffler  17  is neither or only insignificantly enlarged, so that here neither any visual restriction of the driver has to be feared. 
   Furthermore, the outlets  15   b ,  16   b  are directed backwards in the direction of motion F and over the chassis  2  (for example a roof  2   a  over the work place  5 ), however, they can also be directed to the front. 
   In variation to the described and drawn embodiment, the muffler with the two exhaust pipes can also be arranged at other appropriate locations of the finisher  1 . Additional suction means or only suction means can be provided at particularly exposed locations. The two exhaust pipes can also have another cross-section.