Inspection hole in turbomachine casing and plug

Abstract

An inspection hole and plug are provided for an outer casing of a turbomachine. The plug includes an attachment portion configured to removably attach the plug to a coupling portion of the inspection hole. Additionally, the plug includes a tightening portion, a lock nut, and a rod extending through the plug. The lock nut is configured to removably attach the rod to the tightening portion of the plug. The rod also extends into a body of the inspection hole. Further, the inspection hole includes a stepped end positioned proximate to an inner surface of the outer casing to prevent the rod from extending through the outer casing of the turbomachine.

What is claimed is: 
     
         1 . A plug for an inspection hole in a turbomachine, comprising:
 an attachment portion configured to attach the plug to the inspection hole in the turbomachine, the attachment portion defining a through hole;   a tightening portion rigidly attached to the attachment portion, the tightening portion defining a through hole contiguous with the through hole of the attachment portion;   a lock nut removably attached to the tightening portion and moveable to a locked position; and   a rod removably fixed in the through hole of the attachment portion and in the through hole of the tightening portion when the lock nut is in the locked position.   
     
     
         2 . The plug of  claim 1 , wherein the through hole of the attachment portion, the through hole of the tightening portion, and the rod each define a cylindrical shape. 
     
     
         3 . The plug of  claim 1 , wherein the plug is configured to be positioned in an inspection hole defined in an outer casing around a compressor of the turbomachine. 
     
     
         4 . The plug of  claim 1 , wherein the plug further comprises one or more wedge rings positioned between a portion of the lock nut and the tightening portion, wherein the one or more wedge rings press against the rod when the lock nut is in the locked position such that the rod is removably fixed in position. 
     
     
         5 . The plug of  claim 1 , wherein the inspection hole is a borescope hole. 
     
     
         6 . The plug of  claim 1 , wherein the rod comprises a pull ring positioned at a distal end of the rod. 
     
     
         7 . The plug of  claim 1 , further comprising a tether configured to attach the attachment portion, the tightening portion, or both to the rod. 
     
     
         8 . The plug of  claim 1 , wherein the rod is comprised of stainless steel. 
     
     
         9 . A turbomachine system comprising:
 a compressor;   a turbine positioned downstream of the compressor;   a combustor assembly configured between the compressor and the turbine;   an outer casing positioned around at least a portion of the compressor, the turbine, or both and defining an outer surface and an inner surface, wherein the outer casing defines an inspection hole extending therethrough and the inspection hole defines
 a coupling portion adjacent to the outer surface of the outer casing; 
 a body extending from the coupling portion towards the inner surface of the outer casing; and 
 a stepped end positioned adjacent to the inner surface of the outer casing; and 
 a plug removably attached to the coupling portion of the inspection hole, at least a portion of the plug extending into the body of the inspection hole towards the stepped end of the inspection hole. 
   
     
     
         10 . The system of  claim 9 , wherein the inspection hole is defined in the outer casing positioned around the compressor of the turbomachine. 
     
     
         11 . The system of  claim 9 , wherein the body of the inspection hole defines a diameter and the stepped end of the inspection hole defines a diameter, and wherein the diameter of the stepped end is less than the diameter of the body. 
     
     
         12 . The system of  claim 9 , wherein the stepped end is positioned within about L inches from the inner surface of the outer casing, wherein L is less than or equal to about two thirds of the diameter of the body of the inspection hole. 
     
     
         13 . The system of  claim 9 , wherein the inspection hole is a borescope hole. 
     
     
         14 . The system of  claim 9 , further comprising a plurality of inspection holes in the outer casing and a plurality of plugs positioned in the inspection holes, the plurality of inspection holes positioned proximate to two or more stages defined by the compressor portion, wherein the plurality of plugs each include a rod, and wherein the rods from the plurality of plugs are interchangeable. 
     
     
         15 . The turbomachine system of  claim 9 , wherein the plug further comprises:
 an attachment portion defining a through hole, the attachment portion removably attached to the coupling portion of the inspection hole;   a tightening portion rigidly attached to the attachment portion of the plug, the tightening portion defining a through hole contiguous with the through hole of the attachment portion of the plug;   a lock nut removably attached to the tightening portion and moveable to a locked position; and   a rod removably fixed in the through hole of the attachment portion and in the through hole of the tightening portion when the lock nut is in the locked position.   
     
     
         16 . The system of  claim 15 , wherein the diameter of the stepped end is less than a diameter of the rod. 
     
     
         17 . The system of  claim 15 , wherein the rod includes a pull ring positioned at a distal end. 
     
     
         18 . The system of  claim 15 , wherein the plug further comprises a tether configured to attach the attachment portion, the tightening portion, or both to the rod. 
     
     
         19 . The system of  claim 15 , wherein the plug further comprises one or more wedge rings positioned between a portion of the lock nut and the tightening portion, wherein the one or more wedge rings press against the rod when the lock nut is in the locked position such that the rod is removably fixed in position. 
     
     
         20 . The system of  claim 15 , wherein the through hole of the attachment portion, the through hole of the tightening portion, and the rod each define a cylindrical shape.