Turbine exhaust arrangement

Abstract

An exhaust arrangement for a turbine is provided having an inner turbine casing, a condenser, an exhaust arrangement structure, and a bearing cone. The inner turbine casing includes a plurality of last stage buckets. A steam flow passes through the inner turbine casing and out of the plurality of last stage buckets. The condenser for receives the steam flow. The exhaust arrangement structure has a diffuser, a lower section and an upper section. The lower section has an exhaust section. The lower section receives the steam flow from the last stage buckets of the inner turbine casing through the diffuser and guides the steam flow out of the exhaust section in a direction generally towards the condenser. The upper section has a receiving section and a guiding section.

1 . An exhaust arrangement for a turbine, comprising:
 an inner turbine casing including a plurality of last stage buckets, a steam flow passing through the inner turbine casing and out of the plurality of last stage buckets;   a condenser for receiving the steam flow;   an exhaust arrangement structure comprising:
 a diffuser for guiding the steam flow out of the plurality of last stage buckets of the inner turbine casing; 
 a lower section having an exhaust section, the lower section receiving the steam flow from the plurality last stage buckets of the inner turbine casing through the diffuser and guiding the steam flow out of the exhaust section in a direction generally towards the condenser; 
 an upper section having a receiving section and a guiding section, the receiving section receiving the steam flow from the plurality of last stage buckets of the inner turbine casing through the diffuser and the guiding section oriented in a direction generally radially outwardly from a center axis of the turbine and in fluid communication with the receiving section, and the exhaust section of the lower section in fluid communication with the guiding section to direct the steam flow into the condenser; and 
   a bearing cone positioned along the center axis of the turbine and partially defining the steam flow path in the lower section and the upper section.   
     
     
         2 . The exhaust arrangement of  claim 1 , wherein the exhaust arrangement structure is attached to a downstream end of the inner turbine casing. 
     
     
         3 . The exhaust arrangement of  claim 1 , comprising a plurality of steam guides, wherein the diffuser and the steam guides cooperate together to guide the steam flow out of the plurality of last stage buckets of the inner turbine casing. 
     
     
         4 . The exhaust flow arrangement of  claim 1 , wherein the bearing cone is positioned within the exhaust arrangement structure, and partially defines the lower section and the upper section. 
     
     
         5 . The exhaust flow arrangement of  claim 1 , wherein the exhaust arrangement structure includes a flow diffusion portion, wherein flow diffusion of the steam flow occurs within the flow diffusion portion. 
     
     
         6 . The exhaust flow arrangement of  claim 5 , wherein the flow diffusion portion includes a height that is measured between an end wall of the exhaust arrangement structure and an outer surface of the exhaust arrangement structure. 
     
     
         7 . The exhaust flow arrangement of  claim 6 , wherein the height is adjustable depending on the system requirements of the turbine. 
     
     
         8 . The exhaust flow arrangement of  claim 7 , wherein increasing the height results in a greater Effective Area Ratio (EAR), and wherein the EAR is the ratio between an inlet of the exhaust arrangement structure and an outlet of the exhaust arrangement structure. 
     
     
         9 . The exhaust flow arrangement of  claim 1 , wherein a portion of an outer surface of the exhaust arrangement structure includes a filleted edge, and wherein an inner wall of the exhaust arrangement structure corresponds to the filleted edge. 
     
     
         10 . The exhaust flow arrangement of  claim 1 , wherein the turbine is a double flow steam turbine. 
     
     
         11 . A steam turbine, comprising:
 an inner turbine casing having a downstream end and including a plurality of last stage buckets, a steam flow passing through the inner turbine casing and out of the plurality of last stage buckets;   a condenser for receiving the steam flow;   an exhaust arrangement structure attached to a downstream end of the inner turbine casing, the exhaust arrangement structure comprising:
 a diffuser for guiding the steam flow out of the plurality of last stage buckets of the inner turbine casing; 
 a lower section having an exhaust section, the lower section receiving the steam flow from the plurality of last stage buckets of the inner turbine casing through the diffuser and guiding the steam flow out of the exhaust section; 
 an upper section having a receiving section and a guiding section, the receiving section receiving the steam flow from the plurality of last stage buckets of the inner turbine casing through the diffuser and the guiding section oriented in a direction generally radially outwardly from a center axis of the turbine and in fluid communication with the receiving section, and the exhaust section of the lower section in fluid communication with the guiding section to direct the steam flow into the condenser; and 
   a bearing cone positioned along the center axis of the and within the exhaust arrangement structure, the bearing cone partially defining the steam flow path in the lower section and the upper section.   
     
     
         12 . The steam turbine of  claim 11 , comprising a plurality of steam guides, wherein the diffuser and the steam guides cooperate together to guide the steam flow out of the plurality of last stage buckets of the inner turbine casing. 
     
     
         13 . The steam turbine of  claim 11 , wherein the exhaust arrangement structure includes a flow diffusion portion, wherein flow diffusion of the steam flow occurs within the flow diffusion portion. 
     
     
         14 . The steam turbine of  claim 13 , wherein the flow diffusion portion includes a height that is measured between an end wall of the exhaust arrangement structure and an outer surface of the exhaust arrangement structure. 
     
     
         15 . The steam turbine of  claim 14 , wherein the height is adjustable depending on the system requirements of the turbine. 
     
     
         16 . The steam turbine of  claim 15 , wherein increasing the height results in a greater Effective Area Ratio (EAR), and wherein the EAR is the ratio between an inlet of the exhaust arrangement structure and an outlet of the exhaust arrangement structure. 
     
     
         17 . The steam turbine of  claim 11 , wherein a portion of an outer surface of the exhaust arrangement structure includes a filleted edge, and wherein an inner wall of the exhaust arrangement structure corresponds to the filleted edge. 
     
     
         18 . The steam turbine of  claim 11 , wherein the turbine is a double flow steam turbine. 
     
     
         19 . A steam turbine, comprising:
 an inner turbine casing including a plurality of last stage buckets, a steam flow passing through the inner turbine casing and out of the plurality of last stage buckets;   a condenser for receiving the steam flow;   an exhaust arrangement structure comprising:
 a diffuser for guiding the steam flow out of the plurality of last stage buckets of the inner turbine casing; 
 a lower section having an exhaust section, the lower section receiving the steam flow from the plurality of last stage buckets of the inner turbine casing through the diffuser and guiding the steam flow out of the exhaust section; 
 an upper section having a receiving section and a guiding section, the receiving section receiving the steam flow from the plurality of last stage buckets of the inner turbine casing through the diffuser and the guiding section oriented in a direction generally radially outwardly from a center axis of the turbine and in fluid communication with the receiving section, and the exhaust section of the lower section in fluid communication with the guiding section to direct the steam flow into the condenser; 
 a flow diffusion portion where flow diffusion of the steam flow occurs, the flow diffusion portion including a height that is measured between an end wall of the exhaust arrangement structure and an outer surface of the exhaust arrangement structure, the height being adjustable depending on the system requirements of the steam turbine; and 
   a bearing cone positioned along the center axis of the and within the exhaust arrangement structure, the bearing cone partially defining the steam flow path in the lower section and the upper section.   
     
     
         20 . The steam turbine of  claim 19 , comprising a plurality of steam guides, wherein the diffuser and the steam guides cooperate together to guide the steam flow out of the plurality of last stage buckets of the inner turbine casing.