Systems and Methods to Control Variable Stator Vanes in Gas Turbine Engines

Abstract

Embodiments of the present application include a variable stator vanes control mechanism for a gas turbine engine. The control mechanism includes a moveable actuation rod in operative communication with a first unison ring such that movement of the actuation rod drives the first unison ring. The control mechanism also includes a bell crank mechanism in operative communication with the first unison ring and a second unison ring such that movement of the first unison ring drives the second unison ring.

That which is claimed: 
     
         1 . A variable stator vanes control mechanism for a gas turbine engine, comprising:
 a first unison ring;   a second unison ring;   a moveable actuation rod in operative communication with the first unison ring such that movement of the actuation rod drives the first unison ring in a first direction; and   a bell crank mechanism in operative communication with the first unison ring and the second unison ring such that movement of the first unison ring in the first direction drives the second unison ring in a second direction.   
     
     
         2 . The control mechanism of  claim 1 , wherein the second direction is opposite the first direction. 
     
     
         3 . The control mechanism of  claim 1 , wherein the second direction is similar to the first direction. 
     
     
         4 . The control mechanism of  claim 1 , wherein the bell crank mechanism comprises:
 a pivot;   a first turnbuckle operatively connecting the first unison ring to the pivot; and   a second turnbuckle operatively connecting the second unison ring to the pivot.   
     
     
         5 . The control mechanism of  claim 4 , wherein the first turnbuckle and the second turnbuckle are attached to the pivot such that rotation of the pivot drives the first turnbuckle and the second turnbuckle in opposite directions. 
     
     
         6 . The control mechanism of  claim 4 , wherein a relative movement between the first unison ring and the second unison ring can be varied by varying the dimensions of the pivot, the first turnbuckle, and the second turnbuckle. 
     
     
         7 . The control mechanism of  claim 1 , wherein the first unison ring is in operative communication with a plurality of variable stator vanes. 
     
     
         8 . The control mechanism of  claim 1 , wherein the second unison ring is in operative communication with a plurality of variable stator vanes. 
     
     
         9 . The control mechanism of  claim 1 , wherein the bell crank mechanism is at least partially secured to a casing of a compressor. 
     
     
         10 . The control mechanism of  claim 1 , wherein the moveable actuator rod is at least partially secured to a casing of a compressor. 
     
     
         11 . The control mechanism of  claim 1 , further comprising one or more additional unison rings in operative communication with the bell crank mechanism such that movement of the first unison ring in the first direction drives the one or more additional unison rings in the first or second direction respectively. 
     
     
         12 . A method to control variable stator vanes in a gas turbine engine, comprising:
 actuating a moveable actuation rod in operative communication with a first unison ring such that movement of the actuation rod drives the first unison ring in a first direction; and   driving a bell crank mechanism in operative communication with the first unison ring and a second unison ring such that movement of the first unison ring in the first direction drives the second unison ring in a second direction.   
     
     
         13 . The method of  claim 12 , wherein the second direction is opposite the first direction. 
     
     
         14 . The method of  claim 12 , wherein the second direction is similar to the first direction. 
     
     
         15 . A variable stator vanes control mechanism for a gas turbine engine, comprising:
 a compressor having a compressor casing;   a first unison ring disposed about the compressor casing;   a second unison ring disposed about the compressor casing;   a moveable actuation rod attached to the compressor casing and in operative communication with the first unison ring such that movement of the actuation rod drives the first unison ring in a first direction about the compressor casing; and   a bell crank mechanism attached to the compressor casing and in operative communication with the first unison ring and the second unison ring such that movement of the first unison ring about the compressor casing in the first direction drives the second unison ring in a second direction about the compressor casing.   
     
     
         16 . The control mechanism of  claim 15 , wherein the second direction is opposite the first direction. 
     
     
         17 . The control mechanism of  claim 15 , wherein the second direction is similar to the first direction. 
     
     
         18 . The control mechanism of  claim 15 , wherein the bell crank mechanism comprises:
 a pivot;   a first turnbuckle operatively connecting the first unison ring to the pivot; and   a second turnbuckle operatively connecting the second unison ring to the pivot.   
     
     
         19 . The control mechanism of  claim 18 , wherein a relative movement between the first unison ring and the second unison ring can be varied by varying the dimensions of the pivot, the first turnbuckle, and the second turnbuckle. 
     
     
         20 . The control mechanism of  claim 15 , wherein the first unison ring and the second unison ring are in operative communication with a plurality of respective variable stator vanes.