Optical viewing system for monitoring a wide angle area of interest exposed to high temperature

Abstract

The present invention comprises a wide angle lens optical viewing system for the non-destructive monitoring of a high temperature area of interest with a confined space access, in particular, in a gas turbine engine. A novel cooling scheme is claimed that functions to cool the wide angle lens. Further, a method of monitoring an annular combustor region in the gas turbine via the optical viewing system is presented.

1 . An optical viewing system for the non-destructive monitoring of a high temperature area of interest with a confined space access, comprising: 
 an IR imaging device;    an optical probe, having a shaft, a wide angle IR objective lens, and a relay optics unit;    a cooling system adapted to cool the wide angle IR objective lens; and    a processor that converts a detected image to a digital signal and display the digital signal on a visual monitor.    
     
     
         2 . The viewing system as claimed in  claim 1 , wherein the high temperature, closed area of interest is a combustion chamber.  
     
     
         3 . The viewing system as claimed in  claim 2 , wherein a plurality of viewing systems are used to view a plurality of combustion chambers, the plurality of combustion chambers arranged annularly on a combustion turbine.  
     
     
         4 . The viewing system as claimed in  claim 1 , wherein the optical probe is located in a port in a turbine having a cylinder.  
     
     
         5 . The viewing system as claimed in  claim 1 , wherein the wide angle IR objective lens is cooled.  
     
     
         6 . The viewing system as claimed in  claim 1 , wherein the wide angle IR objective lens is cooled with cooling flow from a compressor connected to the turbine.  
     
     
         7 . The viewing system as claimed in  claim 1 , further comprising a plurality of relay optical units arranged within the optical probe.  
     
     
         8 . The viewing system as claimed in  claim 1 , wherein the IR viewing device is an IR camera.  
     
     
         9 . The viewing system as claimed in  claim 1 , wherein the integration time is greater than 3 micro-seconds.  
     
     
         10 . The viewing system as claimed in  claim 8 , wherein the IR camera operates with a frequency in the range of 0.9 μm to 12 μm.  
     
     
         11 . The viewing system as claimed in  claim 1 , wherein the wide angle IR objective lens is made of germanium.  
     
     
         12 . The viewing system as claimed in  claim 1 , wherein the wide angle IR objective lens is made from a material selected from the group consisting of germanium, barium fluoride, zinc selinide, and the like.  
     
     
         13 . The viewing system as claimed in  claim 2 , wherein the wide angle IR objective lens is coated with a material having a frequency that matches the operating frequency of the IR camera.  
     
     
         14 . An optical probe for monitoring an annular combustion chamber within the turbine, comprising: 
 a shaft having a first end and a second end;    a wide angle IR objective lens arranged towards the first end of the shaft; and    a cooling hole arranged toward the first end of the shaft and adjacent to the wide angle IR objective lens to provide cooling air to the wide angle IR objective lens.    
     
     
         15 . The probe as claimed in  claim 14 , further comprising a relay optics unit.  
     
     
         16 . The probe as claimed in  claim 14 , wherein the shaft is made of stainless steel.  
     
     
         17 . The probe as claimed in  claim 14 , wherein the shaft has a cooling port for cooling air to enter.  
     
     
         18 . The probe as claimed in  claim 14 , wherein the shaft is adapted to allow cooling air to enter through a plurality of cooling ports.  
     
     
         19 . The probe as claimed in  claim 14 , wherein a plurality of cooling holes provide cooling air to the wide angle IR objective lens.  
     
     
         20 . The probe as claimed in  claim 19 , wherein the cooling holes are evenly spaced relative to the wide angle IR objective lens.  
     
     
         21 . The probe as claimed in  claim 19 , wherein the cooling hole geometry is selected from the set of cooling hole geometries consisting of a shaped hole, a fan shaped hole, a hole with a diffuser, a slot, a rectangle, an ellipse, and the like, and combinations thereof.  
     
     
         22 . The probe as claimed in  claim 19 , wherein the cooling holes are located peripherally to the wide angle IR objective lens.  
     
     
         23 . The probe as claimed in  claim 19 , wherein pairs of cooling holes are arranged peripherally to the wide angle IR objective lens and extend radially from the center of the optical probe.  
     
     
         24 . The probe as claimed in  claim 19 , wherein more than two cooling holes are arranged peripherally to the wide angle IR objective lens and extend radially from the center of the optical probe.  
     
     
         25 . A method for monitoring an annular combustion chamber in an operating turbine generator, comprising: 
 attaching an appropriate wide angle IR lens to a probe tip of an optical probe;    installing the optical probe in the annular combustion chamber;    operating the turbine;    focusing a lens in the optical probe;    capturing an image with an IR camera; and    processing the captured image.