Noise Eliminator for Fuel Cell

Abstract

A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from the fuel cell, comprising an inner pipe having a plurality of sound transmission holes formed in its peripheral wall and allowing the exhaust gases to flow therethrough and an outer shell disposed to surround the inner pipe through a prescribed distance from the peripheral wall and constituting a sound absorbing chamber with a sound absorbing material filled in the clearance thereof from the inner pipe. The sound transmission hole has an inner diameter of 3 mm or greater, and a depth of 1.2 mm or less.

1 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the sound transmission hole has an inner diameter of 3 mm or greater and a depth of 1.2 mm or less.   
   
   
       2 . The noise eliminator for a fuel cell according to  claim 1 , wherein the peripheral part of the sound transmission hole in the inner pipe is formed with a wall thickness thinner than that of other parts of the sound transmission hole. 
   
   
       3 . The noise eliminator for a fuel cell according to  claim 1 , wherein a rib reinforcing the inner pipe is formed between the sound transmission holes. 
   
   
       4 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the sound transmission hole is formed in the shape of an oval having a longitudinal axis along the axis direction of the inner pipe.   
   
   
       5 . The noise eliminator for a fuel cell according to  claim 4 , wherein the direction of the longitudinal axis of the oval being the sound transmission hole is substantially parallel to the axis of the inner pipe. 
   
   
       6 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein there is formed a groove connecting the adjoining sound transmission holes.   
   
   
       7 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the inner wall of the sound transmission hole is formed in a saw-tooth shape.   
   
   
       8 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein a water repellant layer is formed in the inner wall of the sound transmission hole.   
   
   
       9 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein a sound absorbing material is filled in the inner side of the inner wall of the sound transmission hole.   
   
   
       10 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the inner pipe is provided with a stream drift member drifting an exhaust gas stream in such a manner that the exhaust gas stream is prevented from directly impacting the sound transmission hole, and   wherein the stream drift member is a louver in the inner-pipe inner wall, protruding in a manner inclined from the upstream side of the sound transmission hole towards a downstream direction.   
   
   
       11 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the inner pipe is provided with a stream drift member drifting an exhaust gas stream in such a manner that the exhaust gas stream is prevented from directly impacting the sound transmission hole, and   wherein the stream drift member is a stream guide plate, provided at an upstream end of the inner pipe, and guiding the exhaust gas stream to an area where no sound transmission hole is formed.   
   
   
       12 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein a swirling flow generation member generating a swirling flow along the inner-pipe inner wall is provided in an upstream end of the inner pipe.   
   
   
       13 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein a vortex generation member generating a vortex in the vicinity of the inner-pipe inner wall is provided in the inner pipe.   
   
   
       14 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   the noise eliminator further comprising stream guide means for causing a portion of the exhaust gas flowing into the inner pipe to flow out from inside the inner pipe through the upstream-side sound transmission holes to the sound absorbing chamber,   wherein the exhaust gas flowing out to the sound absorbing chamber flows through the downstream-side sound transmission holes back into the inner pipe.   
   
   
       15 . The noise eliminator for a fuel cell according to  claim 14 , wherein the stream guide means is a narrowed portion formed in the path of the inner pipe. 
   
   
       16 . The noise eliminator for a fuel cell according to  claim 14 , wherein the stream guide means is a duct arranged in the inner-pipe inner wall in a manner corresponding to the upstream-side sound transmission hole. 
   
   
       17 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   the noise eliminator further comprising gas injection means for injecting gas from outside the noise eliminator directly to the sound absorbing chamber so that gas flows from the sound absorbing chamber through the sound transmission holes into the inner pipe.   
   
   
       18 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an inner pipe having a plurality of sound transmission holes formed in a peripheral wall thereof and allowing exhaust gas to flow therethrough; and   an outer shell, arranged to surround the inner pipe up to a prescribed distance from the peripheral wall, and constituting a sound absorbing chamber with a sound absorbing material filled in a space between the outer shell and the inner pipe,   wherein the sound transmission hole and a peripheral part thereof are formed in a manner projecting towards the axis center of the inner pipe.   
   
   
       19 . A noise eliminator for a fuel cell installed in an exhaust system discharging exhaust gas from a fuel cell, the noise eliminator comprising:
 an outer shell allowing exhaust gas to flow therethrough; and   an inner case having a plurality of through holes formed in a peripheral wall thereof and constituting a sound absorbing chamber with a sound absorbing material filled in the interior thereof,   wherein the inner case is arranged over the entire stream path cross section of the outer shell such that all the exhaust gas flowing through the outer shell flows through the interior of the inner case.   
   
   
       20 . (canceled)