Variable area diffuser

Abstract

A diffuser assembly for a compressor is provided. The diffuser may include a first stationary wall and a second stationary wall coupled with one another and forming at least in part a volute configured to receive compressed process fluid from the diffuser. The second stationary wall may define a plurality of stationary wall grooves. The diffuser may also include a moveable wall defining a plurality of moveable wall grooves. The moveable wall may be disposed between the first stationary wall and the second stationary wall such that respective stationary wall grooves and moveable wall grooves form respective flow passages configured to receive the flow of process fluid exiting an impeller of the compressor. The diffuser assembly may also include an actuator assembly configured to displace the moveable wall to alter a cross-sectional area of each of the flow passages based on a flow rate of the process fluid.

I claim: 
     
         1 . A diffuser assembly for a compressor, comprising:
 a diffuser disposable about an impeller of the compressor and configured to receive and compress a flow of process fluid exiting the impeller, the diffuser comprising
 a first stationary wall and a second stationary wall coupled with one another and forming at least in part a volute configured to receive the compressed process fluid from the diffuser, the second stationary wall defining a plurality of stationary wall grooves; and 
 a moveable wall defining a plurality of moveable wall grooves, the moveable wall disposed between the first stationary wall and the second stationary wall such that respective stationary wall grooves and moveable wall grooves form respective flow passages configured to receive the flow of process fluid exiting the impeller; and 
   an actuator assembly comprising at least one actuator and at least one linkage operatively coupling the at least one actuator and the moveable wall, the actuator assembly configured to displace the moveable wall to alter a cross-sectional area of each of the flow passages.   
     
     
         2 . The diffuser assembly of  claim 1 , wherein the moveable wall comprises a first annular face and a second annular face axially opposing the first annular face, the first annular face adjacent the first stationary wall and operatively coupled with the at least one actuator via the at least one linkage. 
     
     
         3 . The diffuser assembly of  claim 2 , wherein the second annular face defines the plurality of moveable wall grooves and comprises a plurality of projections extending from the second annular face, each projection disposed between adjacent moveable wall grooves. 
     
     
         4 . The diffuser assembly of  claim 3 , wherein the second stationary wall further defines a plurality of recesses, each recess being disposed between adjacent stationary wall grooves and configured to receive therein a respective projection of the plurality of projections. 
     
     
         5 . The diffuser assembly of  claim 1 , wherein:
 the at least one actuator comprises a first actuator and a second actuator, and   the at least one linkage comprises a first linkage and a second linkage, the first actuator being operative coupled to the moveable wall via the first linkage, and the second actuator being operatively coupled to the moveable wall via the second linkage.   
     
     
         6 . The diffuser assembly of  claim 5 , wherein the actuator assembly further comprises a first seal disposed about the first linkage, and a second seal disposed about the second linkage, the first seal and the second seal configured to substantially reduce or eliminate leakage of the process fluid from the compressor while permitting axial displacement of the first linkage and the second linkage, respectively, relative to the compressor. 
     
     
         7 . The diffuser assembly of  claim 1 , wherein the first stationary wall defines at least one aperture extending axially therethrough, and the at least one linkage is configured to extend through the at least one aperture to operatively couple the at least one actuator and the moveable wall. 
     
     
         8 . The diffuser assembly of  claim 1 , wherein the diffuser is a pipe diffuser. 
     
     
         9 . The diffuser assembly of  claim 8 , wherein each of the flow passages comprises a throat, and the actuator assembly is further configured to axially displace the moveable wall to reduce or increase the throat of each of the flow passages. 
     
     
         10 . The diffuser assembly of  claim 9 , wherein at least a portion of each of the flow passages extends parallel to the axial displacement of the moveable wall. 
     
     
         11 . A compressor, comprising:
 a casing having an inlet and defining an impeller cavity;   a rotary shaft configured to be driven by a driver;   an impeller fluidly coupled with the inlet and disposed in the impeller cavity, the impeller coupled to the rotary shaft and configured to rotate with the rotary shaft to impart energy to process fluid received via the inlet, the impeller further configured to discharge the process fluid in at least a partially radial direction;   a diffuser disposed circumferentially about the impeller and configured to receive and compress the process fluid discharged from the impeller, the diffuser comprising
 a first stationary wall coupled with the casing; 
 a second stationary wall coupled with the first stationary wall and the casing and defining a plurality of stationary wall grooves; and 
 a moveable wall defining a plurality of moveable wall grooves, the moveable wall disposed between the first stationary wall and the second stationary wall such that respective stationary wall grooves and moveable wall grooves form respective flow passages configured to receive the flow of process fluid discharged from the impeller; 
   a collector formed at least in part by the first stationary wall and the second stationary wall, the collector configured to receive the compressed process fluid from the flow passages of the diffuser; and   an actuator assembly comprising at least one actuator and at least one linkage operatively coupling the at least one actuator and the moveable wall, the actuator assembly configured to displace the moveable wall to alter a cross-sectional area of each of the flow passages.   
     
     
         12 . The compressor of  claim 11 , wherein:
 each stationary wall groove of the plurality of stationary wall grooves extends in a tangential orientation about the impeller; and   each moveable wall groove of the plurality of moveable wall grooves extends in a tangential orientation about the impeller.   
     
     
         13 . The compressor of  claim 12 , wherein:
 the diffuser is a pipe diffuser; and   each of the flow passages comprises a throat, and the actuator assembly is further configured to axially displace the moveable wall to reduce or increase the throat of each of the flow passages.   
     
     
         14 . The compressor of  claim 12 , wherein:
 the first stationary wall defines at least one aperture extending axially therethrough, and the at least one linkage is configured to extend through the at least one aperture to operatively couple the at least one actuator and the moveable wall; and   the moveable wall comprises a first annular face and a second annular face axially opposing the first annular face, the first annular face adjacent the first stationary wall and operatively coupled with the at least one actuator via the at least one linkage.   
     
     
         15 . The compressor of  claim 13 , wherein:
 the second annular face defines the plurality of moveable guide vanes and comprises a plurality of projections extending from the second annular face, each projection disposed between adjacent moveable wall grooves; and   the second stationary wall further defines a plurality of recesses, each recess being disposed between adjacent stationary wall grooves and configured to receive therein a respective projection of the plurality of projections.   
     
     
         16 . A method for adjusting a cross-sectional area of a flow passage of a diffuser in a compressor, comprising:
 monitoring one or more operating parameters of the compressor or a process fluid flowing therethrough;   detecting an operating parameter of the one or more operating parameters outside of a predetermined range; and   axially displacing a moveable wall of the diffuser via at least one actuator operatively coupled with the moveable wall via at least one linkage, the axial displacement of the moveable wall adjusting the cross-sectional area of the flow passage of the diffuser.   
     
     
         17 . The method of  claim 16 , wherein:
 the diffuser further comprises a first stationary wall and the second stationary wall coupled with one another and forming at least in part a volute configured to receive the process fluid from the diffuser;   the second stationary wall defines a plurality of stationary wall grooves; and   the moveable wall defining a plurality of moveable wall grooves, the moveable wall disposed between the first stationary wall and the second stationary wall such that respective stationary wall grooves and moveable wall grooves form respective flow passages.   
     
     
         18 . The method of  claim 17 , wherein:
 the first stationary wall defines at least one aperture extending axially therethrough, and the at least one linkage is configured to extend through the at least one aperture to operatively couple the at least one actuator and the moveable wall; and   the moveable wall comprises a first annular face and a second annular face axially opposing the first annular face, the first annular face adjacent the first stationary wall and operatively coupled with the at least one actuator via the at least one linkage.   
     
     
         19 . The method of  claim 18 , wherein:
 the second annular face defines the plurality of moveable guide vanes and comprises a plurality of projections extending from the second annular face, each projection disposed between adjacent moveable wall grooves; and   the second stationary wall further defines a plurality of recesses, each recess being disposed between adjacent stationary wall grooves and configured to receive therein a respective projection of the plurality of projections.   
     
     
         20 . The method of  claim 18 , wherein each of the flow passages comprises a throat, and axially displacing the moveable wall of the diffuser via the at least one actuator operatively coupled with the moveable wall via the at least one linkage comprises:
 increasing or decreasing the throat of each of the flow passages.