Compressor sound suppression

Abstract

A compressor includes a housing and one or more working elements. A muffler is located downstream of the discharge plenum. A centerbody is located in the discharge plenum upstream of the muffler spanning a major portion of a length between a bearing case and the muffler.

1 . A method for remanufacturing a compressor or reengineering a configuration of the compressor comprising: 
 providing an initial such compressor or configuration having: 
 a housing;  
 a first rotor having a first rotational axis;  
 a second rotor having a second rotational axis and enmeshed with the first rotor;  
 a third rotor having a third rotational axis and enmeshed with the first rotor; and  
 a discharge plenum; and  
   placing a centerbody in the discharge plenum.    
   
   
       2 . The method of  claim 1  wherein: 
 the placing locates the centerbody upstream of a muffler having an essentially annular principal flowpath segment between inner and outer sound absorbing means.    
   
   
       3 . The method of  claim 1  wherein: 
 the placing leaves the housing and the first, second, and third rotors essentially unchanged.    
   
   
       4 . The method of  claim 1  further comprising: 
 selecting a geometry of the centerbody so as to reduce a pressure drop across the discharge plenum.    
   
   
       5 . The method of  claim 4  wherein: 
 the selecting of the geometry comprises selecting a streamwise variation in centerbody cross-section.    
   
   
       6 . The method of  claim 4  further comprising: 
 measuring the parameter reflecting the pressure drop across the discharge plenum.    
   
   
       7 . The method of  claim 1  further comprising: 
 selecting a geometry of the centerbody so as to reduce a sound emitted from the discharge plenum.    
   
   
       8 . The method of  claim 7  wherein: 
 the selecting of the geometry also reduces a pressure drop across the discharge plenum.    
   
   
       9 . The method of  claim 7  further comprising: 
 measuring the sound emitted from the discharge plenum.    
   
   
       10 . The method of  claim 1  being said method of manufacturing.  
   
   
       11 . The method of  claim 1  being said method of reengineering.  
   
   
       12 . The method of  claim 1  further comprising: 
 selecting a material of the centerbody to comprise at least one of molded plastic, polymeric foam, and expanded bead material.    
   
   
       13 . The method of  claim 1  wherein: 
 the centerbody spans a majority of a length between a bearing case and the muffler.    
   
   
       14 . The method of  claim 13  wherein: 
 the centerbody essentially extends from the bearing case to the muffler.    
   
   
       15 . The method of  claim 1  wherein: 
 the centerbody smoothes a flow transition between said outlet and the muffler.    
   
   
       16 . The method of  claim 1  wherein: 
 the centerbody has an essentially downstream continuously increasing transverse cross-sectional area.    
   
   
       17 . The method of  claim 1  wherein: 
 a downstream portion of the centerbody has a cross-sectional area at least 20% greater than an upstream portion of the centerbody.    
   
   
       18 . The method of  claim 1  wherein: 
 the centerbody outer surface is essentially divergent in a direction toward the muffler.    
   
   
       19 . A method for engineering a compressor configuration, the compressor configuration comprising: 
 a first rotor having a first rotational axis;    a second rotor having a second rotational axis and enmeshed with the first rotor;    a third rotor having a third rotational axis and enmeshed with the first rotor;    a housing containing the first, second and third rotors and having a bearing case supporting the first, second, and third rotors;    an discharge plenum within the housing;    a muffler downstream of the discharge plenum; and    a body within the discharge plenum and spanning a major portion of a length between a bearing case and the muffler, the method comprising:    measuring a parameter reflecting a pressure drop across the discharge plenum; and    selecting at least one parameter of the body so as to reduce the pressure drop between an initial configuration of the body and a final configuration of the body.    
   
   
       20 . The method of  claim 19  wherein said measuring and a varying of said at least one parameter are performed as an iterative simulation.  
   
   
       21 . The method of  claim 19  wherein said measuring and a varying of said at least one parameter are performed iteratively on an actual compressor.