Blow-Off Silencers

The  Blow-Off  Silencer  consists  of  a  tube  with  a  closed  end  in  which  a  large  number  of  small holes  have been  made, the  number, the  diameter  and  the  pattern  of  the  holes  are  determined by  the  required  silencing value.

The  diameter  of  the  tube  is  generally  the  same  as  the  diameter  of  the  blow-off  pipe  depending on  the diameter  and  configuration  of  the  holes, a  silencing  of  10 – 40 dB(A)  is  achieved.

The  standard  material  of  the  silencer  is  stainless steel, but  other  materials  are  also  available  when  high silencing  values  are  required, the  silencer  is  provided  with  a  specially  designed  casing of   sound-absorbing  material ;  with  this  construction  it  is  possible  to  achieve  a  T.S.D. of   up to   60 dB(A).

Properties  :

When  steam  and  gases  are  blown  off  under  pressure, high  sound  levels  are  generated ,

  • With  the  BLOW-OFF  SILENCER  these  levels  can  be  reduced  to  the  acceptable  levels
  • The  sound  generated  during  blow-off  via  a  BLOW-OFF  SILENCER  lies  to  a  large  extent  in the  inaudible  area  for  humans ;  and  this  is  where  the  operation  of  the  silencer  lies !
  • In  principle, the  silencer  can  be  designed  such  that  during  blow-off  the  loss  of  pressure over  the  silencer  is  negligible, this  may  be  important  when, for  example, the  silencer  is installed  behind  a  Safety  Valve  or  a  reservoir  needs  to  blow- off  in  a  short  space  of  time
  • Due  to  the  small  dimensions  and  small  mass  (usually  less  than  100 kg),
  • The  silencer  can  be  installed  directly  on  the  blow-off  pipe  without  an  additional supporting  structure

Both  Suction  and  Discharge  Silencers  shall  be  supplied  either  in  circular  or  rectangular  construction  for  Fan / Blower  and  Turbo  Blowers. The  rectangular  silencer  shall  be  of  absorptive type installed either  at  suction  side  or  at  discharge  side  of  Fan / Blower. The  internals  of  the silencer  comprises  a  series  of  acoustic  splitter  elements  arranged  in  parallel  inside the  rectangular steel casing.  This  would  ensure  the  flow  of  air / gases  through  the  rectangular  air  gap  between  acoustics  splitters  and  thus  offering  a  minimum  pressure  drop.  The  leading  and  trailing  edge  of  the  acoustic  splitters  will  be  designed  aerodynamically  to  offer  minimum  resistance  to  the  flow  medium.


The  effective  noise  reduction  from  our  Blow – Down  Silencers  is  due  to  a  throttle  system  directly behind  the silencer’s  inlet  duct  and  an  absorption  system  consisting  of  splitters. The  throttle system  is  placed  in  a  radial multi – stage  expansion  unit.  The  number  and  size  of  the  throttle sections  depends  upon  the  level  of  the  inlet pressure  and  the  acoustic  requirements. The  gaseous  medium  flows  radically  through  the  throttle  sections, each  section  forming  an  expansion stage.