Apparatus and method of sound attenuation in a system employing a VSD and a quarter-wave resonator

Abstract

A resonator in a closed fluid system includes a body having a passageway in communication with a closed fluid system wherein a piston is movable within the passageway. Each position of the piston within the passageway defines a noise attenuation frequency corresponding to a noise frequency generated by the closed fluid system. A device providing a pressurized fluid from the closed fluid system selectively moves the piston within the passageway to vary the noise attenuation frequency.

1 . A resonator arrangement for a closed fluid system comprising: 
 a body having a passageway in fluid communication with a closed fluid system;    a piston movable within the passageway wherein a position of the piston within the passageway defines a noise attenuation frequency for the closed fluid system;    a control arrangement to selectively position the piston within the passageway to generate a noise attenuation frequency corresponding to a noise frequency generated by the closed fluid system.    
     
     
         2 . The resonator of  claim 1  wherein the control arrangement includes a pressurized fluid to selectively position the piston.  
     
     
         3 . The resonator of  claim 2  wherein the pressurized fluid to selectively position the piston is taken from a pressurized fluid source that is independent of the closed fluid system.  
     
     
         4 . The resonator of  claim 3  wherein the pressurized fluid to selectively position the piston is separated from the fluid in the closed fluid system.  
     
     
         5 . The resonator of  claim 3  wherein the pressurized fluid to selectively position the piston is the same as the fluid in the closed fluid system.  
     
     
         6 . The resonator of  claim 2  wherein the pressurized fluid to selectively position the piston is taken from the closed fluid system.  
     
     
         7 . The resonator of  claim 3  wherein the pressurized fluid provided to selectively position the piston within the passageway in a direction to generate a decreased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is taken from a pressurized fluid source that is independent of the closed fluid system; and 
 wherein the pressurized fluid provided to selectively position the piston within the passageway in a direction to generate an increased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is taken from the closed fluid system.    
     
     
         8 . The resonator of  claim 7  wherein the pressurized fluid taken from the pressurized fluid source that is independent of the closed fluid system is separated from the fluid in the closed fluid system.  
     
     
         9 . The resonator of  claim 3  wherein the pressurized fluid provided to selectively move the piston within the passageway in a direction to generate an increased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is taken from a pressurized fluid source that is independent of the closed fluid system; and 
 wherein the pressurized fluid provided to selectively move the piston within the passageway in a direction to generate a decreased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is taken from the closed fluid system.    
     
     
         10 . The resonator of  claim 9  wherein the pressurized fluid taken from the pressurized fluid source that is independent of the closed fluid system is separated from the fluid in the closed fluid system.  
     
     
         11 . The resonator of  claim 1  wherein the closed fluid system is an HVAC&R system.  
     
     
         12 . The resonator of  claim 11  wherein the HVAC&R system includes a variable speed drive.  
     
     
         13 . The resonator of  claim 1  wherein the control arrangement includes a valve.  
     
     
         14 . The resonator of  claim 1  wherein the control arrangement includes a proportional valve.  
     
     
         15 . The resonator of  claim 1  further comprising a resilient device within the passageway to urge the piston to move in a direction within the passageway.  
     
     
         16 . The resonator of  claim 15  wherein the resilient device is a spring.  
     
     
         17 . The resonator of  claim 15  further comprising a resilient device within the passageway to urge the piston to move in a direction within the passageway toward the closed fluid system.  
     
     
         18 . The resonator of  claim 15  further comprising a resilient device within the passageway to urge the piston to move in a direction within the passageway away from the closed fluid system.  
     
     
         19 . A variable noise attenuation device for use with an HVAC&R fluid system comprising: 
 a body having a passageway in fluid communication with an HVAC&R fluid system;    a piston movable within the passageway wherein a position of the piston within the passageway defining a noise attenuation frequency for the HFAC&R fluid system;    a proportional valve selectively providing a pressurized fluid from the HVAC&R fluid system to the piston to selectively position the piston within the passageway to generate a noise attenuation frequency corresponding to a noise frequency generated by the HFAC&R fluid system.    
     
     
         20 . The variable noise attenuation device of  claim 19  wherein the proportional valve is in fluid communication with a positive displacement compressor.  
     
     
         21 . The variable noise attenuation device of  claim 20  wherein the positive displacement compressor is a screw compressor or a reciprocating compressor.  
     
     
         22 . The variable noise attenuation device of  claim 19  wherein the HVAC&R fluid system is a closed HVAC&R fluid system.  
     
     
         23 . The variable noise attenuation device of  claim 19  wherein the HVAC&R fluid system includes a variable speed drive.  
     
     
         24 . A method for attenuating noise in a closed fluid system, the steps comprising: 
 providing a body having a passageway in fluid communication with a closed fluid system;    providing a piston movable within the passageway wherein a position of the piston within the passageway defines a noise attenuation frequency for the closed fluid system;    providing a control arrangement for providing a pressurized fluid to the piston; and    positioning selectively the piston within the passageway to generate a noise attenuation frequency corresponding to a noise frequency generated by the closed fluid system.    
     
     
         25 . The method of  claim 24  wherein the step of providing the control arrangement for providing the pressurized fluid to the piston includes providing the pressurized fluid from a pressurized fluid source that is independent of the closed fluid system.  
     
     
         26 . The method of  claim 25  wherein the step of providing the control arrangement for providing the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system further includes the step of separating the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system from the fluid in the closed fluid system.  
     
     
         27 . The method of  claim 25  wherein the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system is the same as the fluid in the closed fluid system.  
     
     
         28 . The method of  claim 24  wherein the step of providing the control arrangement for providing the pressurized fluid to the piston includes providing the pressurized fluid taken from the closed fluid system.  
     
     
         29 . The method of  claim 25  wherein the step of providing the control arrangement for providing the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to the piston includes providing the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to selectively position the piston within the passageway in a direction to generate a decreased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system; and 
 providing the control arrangement for providing the pressurized fluid from the closed fluid system to selectively position the piston within the passageway in a direction to generate an increased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system.    
     
     
         30 . The method of  claim 29  wherein the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to selectively position the piston within the passageway in a direction to generate the decreased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is separated from the fluid in the closed fluid system.  
     
     
         31 . The method of  claim 25  wherein the step of providing the control arrangement for providing the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to the piston includes providing the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to selectively position the piston within the passageway in a direction to generate an increased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system; and 
 providing the pressurized fluid from the closed fluid system to selectively position the piston within the passageway in a direction to generate a decreased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system.    
     
     
         32 . The method of  claim 31  wherein the pressurized fluid from the pressurized fluid source that is independent of the closed fluid system to selectively position the piston within the passageway in a direction to generate an increased noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system is separated from the fluid in the closed fluid system.  
     
     
         33 . The method of  claim 24  wherein the closed fluid system is an HVAC&R system.  
     
     
         34 . The method of  claim 33  wherein the HVAC&R system includes a variable speed drive.  
     
     
         35 . The method of  claim 24  wherein the step of providing the control arrangement includes a step of providing a valve.  
     
     
         36 . The method of  claim 24  wherein the step of providing the control arrangement includes providing a proportional valve.  
     
     
         37 . The method of  claim 24  further including an additional step, before the step of providing a control arrangement for providing a pressurized fluid from the closed fluid system to the piston, of providing an algorithm, the step of providing an algorithm further including the steps of 
 reading a variable speed drive frequency output; and    comparing the variable speed drive frequency output to the position of the piston in the passageway; and    wherein the step of positioning selectively the piston within the passageway to generate the noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system includes positioning selectively the piston within the passageway to generate the noise attenuation frequency corresponding to the noise frequency generated by the closed fluid system in response to the algorithm.    
     
     
         38 . The method of  claim 24  further including an additional step, before the step of providing a control arrangement for providing pressurized fluid, of providing a resilient device within the passageway to urge the piston into movement within the passageway toward the closed fluid system.  
     
     
         39 . The method of  claim 38  wherein the resilient device is a spring.