GB2033973A

GB2033973A - Apparatus for Inspecting Internal Components of a Gas Turbine Engine

Info

Publication number: GB2033973A
Application number: GB7933517A
Authority: GB
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1978-11-04
Filing date: 1979-09-27
Publication date: 1980-05-29

Abstract

The apparatus comprises a guide tube 34 which is inserted through an access aperture 22 in the engine casing 12, the guide being movable both rotatably and axially with respect to the aperture and being lockable in any desired position. The internal end 38 of the guide can be located adjacent the component to be inspected, e.g. blades 16, 20, and a flexible endoscope or other remote viewing apparatus is passed through the interior of the guide. <IMAGE>

Description

SPECIFICATION Method and Apparatus for Inspecting Gas Turbine Engines This invention relates to a method and apparatus for inspecting gas turbine engines, particularly components of such engines which are located internally of the engine casing.

The present method of inspecting such components comprises inserting either a rigid or flexible endoscope or other remote viewing inspection apparatus through an access aperture in the engine casing and manoeuvering the endoscope until the component to be inspected is located. This method has the disadvantages of it being difficult to correctly locate the endoscope adjacent the component to be inspected, an uncertainty as to whether the correct component is being viewed, the impossibility of inspecting some internal components in situ and that in some instances only a portion of the component to be inspected can actually be inspected. The present invention seeks to provide a method and apparatus which will constitute an improvement over the existing method.

According to the present invention there is provided a method of inspecting a gas turbine engine, the engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the casing, the method comprising inserting guide means into the access aperture locating one end of the guide means externally of the casing locating the other end of the guide means in said location and inserting a flexible endoscope or other remote viewing inspection apparatus into the guide means.

According to a further aspect of the invention there is provided a gas turbine engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the engine casing, the engine when being inspected having guide means inserted in the access aperture, the guide means having one end located externally of the casing and the other end located adjacent the component to be inspected, the guide means being capable of receiving a flexible endoscope.

In one arrangement the guide means may comprise a suitably shaped tube which is movable relative to the engine casing and can be locked in a predetermined position.

The present invention will now be more particularly described with reference to the accompanying drawings in which: Figure 1 shows a portion of a gas turbine engine according to the present invention, Figure 2 is a part section on line 2-2 in Figure 1 and, Figure 3 shows a diagrammatic view of the whole of the gas turbine engine shown in Figure 1.

Referring to the drawings, a gas turbine engine 10 (only a part of which is shown) comprises a casing 12, a combustion chamber 14, a ring of nozzle guide vanes 16 and a high pressure turbine 18 having blades 20.

The casing 10 has a number of access apertures 22 for inspection purposes, which is normally blanked off by a plate (see Figure 3). In the Figures, a collar 24 is bolted over the aperture, the collar having an offset bore 26, a guide pin 28 and a locking screw 30. Guide means in the form of a curved tube 32 passes through the bore 26, the guide pin 28 engaging a slot 34 in the tube 32 and the locking screw 30 holding the tube in position.

The guide tube 34 is shaped so that it can pass through a dilution air hole 36 in the combustion chamber 14 and the end 38 of the tube is located adjacent the component or components to be inspected which in this case are the vanes 1 6 and blades 20. An endoscope 40 (only a part of which is shown) is passed through the guide tube so that the vanes and blades can be inspected.

Inspection of the complete span of the vanes and blades is achieved by slackening off the lock screw 30 and pushing the guide tube through the bore 26 and since the guide tube cannot rotate in the bore because of the pin 28 engaging the slot 34, the end 38 of the guide tube together with the endoscope 40 will traverse the span of the vanes and blades.

All the blades 20 can be inspected by rotating the turbine disc 1 8 and the vanes can be inspected by re-locating the guide tube and endoscope in other access apertures 22, although more than one vane 16 can be inspected by rotating the guide tube in the bore 26, this being achieved by first removing the pin 28.

It will be seen that by the use of a guide tube the endoscope can be accurately positioned in relation to the component to be inspected and that by having a range of guide tubes to be used in conjunction with various access apertures 22 which can be located at any suitable location in an engine casing (see Figure 3), a large variety of internal engine components can be accurately inspected.

In Figure 3, the gas turbine engine 10 has a number of access apertures 22 located in the intermediate casing, adjacent the combustion chambers (as shown in detail in Figures 1 and 2) in the exhaust annulus and in the inter-turbine duct, each of these apertures being shown more clearly in the drawings forming part of this Figure.

Claims

1. A method of inspecting a gas turbine engine, the engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the casing, the method comprising inserting guide means into the access aperture, locating one end of the guide means externally of the casing, locating the other end of the guide means adjacent the engine component to be inspected, fixing the guide means in said location and inserting a flexible endoscope or other remote

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method and Apparatus for Inspecting Gas Turbine Engines This invention relates to a method and apparatus for inspecting gas turbine engines, particularly components of such engines which are located internally of the engine casing. The present method of inspecting such components comprises inserting either a rigid or flexible endoscope or other remote viewing inspection apparatus through an access aperture in the engine casing and manoeuvering the endoscope until the component to be inspected is located. This method has the disadvantages of it being difficult to correctly locate the endoscope adjacent the component to be inspected, an uncertainty as to whether the correct component is being viewed, the impossibility of inspecting some internal components in situ and that in some instances only a portion of the component to be inspected can actually be inspected. The present invention seeks to provide a method and apparatus which will constitute an improvement over the existing method. According to the present invention there is provided a method of inspecting a gas turbine engine, the engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the casing, the method comprising inserting guide means into the access aperture locating one end of the guide means externally of the casing locating the other end of the guide means in said location and inserting a flexible endoscope or other remote viewing inspection apparatus into the guide means. According to a further aspect of the invention there is provided a gas turbine engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the engine casing, the engine when being inspected having guide means inserted in the access aperture, the guide means having one end located externally of the casing and the other end located adjacent the component to be inspected, the guide means being capable of receiving a flexible endoscope. In one arrangement the guide means may comprise a suitably shaped tube which is movable relative to the engine casing and can be locked in a predetermined position. The present invention will now be more particularly described with reference to the accompanying drawings in which: Figure 1 shows a portion of a gas turbine engine according to the present invention, Figure 2 is a part section on line 2-2 in Figure 1 and, Figure 3 shows a diagrammatic view of the whole of the gas turbine engine shown in Figure 1. Referring to the drawings, a gas turbine engine 10 (only a part of which is shown) comprises a casing 12, a combustion chamber 14, a ring of nozzle guide vanes 16 and a high pressure turbine 18 having blades 20. The casing 10 has a number of access apertures 22 for inspection purposes, which is normally blanked off by a plate (see Figure 3). In the Figures, a collar 24 is bolted over the aperture, the collar having an offset bore 26, a guide pin 28 and a locking screw 30. Guide means in the form of a curved tube 32 passes through the bore 26, the guide pin 28 engaging a slot 34 in the tube 32 and the locking screw 30 holding the tube in position. The guide tube 34 is shaped so that it can pass through a dilution air hole 36 in the combustion chamber 14 and the end 38 of the tube is located adjacent the component or components to be inspected which in this case are the vanes 1 6 and blades 20. An endoscope 40 (only a part of which is shown) is passed through the guide tube so that the vanes and blades can be inspected. Inspection of the complete span of the vanes and blades is achieved by slackening off the lock screw 30 and pushing the guide tube through the bore 26 and since the guide tube cannot rotate in the bore because of the pin 28 engaging the slot 34, the end 38 of the guide tube together with the endoscope 40 will traverse the span of the vanes and blades. All the blades 20 can be inspected by rotating the turbine disc 1 8 and the vanes can be inspected by re-locating the guide tube and endoscope in other access apertures 22, although more than one vane 16 can be inspected by rotating the guide tube in the bore 26, this being achieved by first removing the pin 28. It will be seen that by the use of a guide tube the endoscope can be accurately positioned in relation to the component to be inspected and that by having a range of guide tubes to be used in conjunction with various access apertures 22 which can be located at any suitable location in an engine casing (see Figure 3), a large variety of internal engine components can be accurately inspected. In Figure 3, the gas turbine engine 10 has a number of access apertures 22 located in the intermediate casing, adjacent the combustion chambers (as shown in detail in Figures 1 and 2) in the exhaust annulus and in the inter-turbine duct, each of these apertures being shown more clearly in the drawings forming part of this Figure. Claims

1. A method of inspecting a gas turbine engine, the engine having a casing which is provided with at least one access aperture to allow inspection of engine components located within the casing, the method comprising inserting guide means into the access aperture, locating one end of the guide means externally of the casing, locating the other end of the guide means adjacent the engine component to be inspected, fixing the guide means in said location and inserting a flexible endoscope or other remote viewing inspection apparatus into the guide means.

2. Apparatus for performing the method as claimed in claim 1 in which the guide means comprises a suitably shaped tube which is movable both rotatably and axially with respect to the access aperture and locking means are provided to secure the tube in a desired position.

3. A method of inspecting a gas turbine engine substantially as herein described and with reference to the accompanying drawings.

4. Apparatus for performing the method as claimed in ciaim 3 constructed and arranged for use and operation substantially as herein described and with reference to the accompanying drawings.