Optical measurement of vane ring throat area

A device for optically measuring throat area in a vane ring for a gas turbine engine, the vane ring having an annular array of vanes defining a plurality of individual throats between adjacent leading and following vanes of the array, each said individual throat being a planar opening with a periphery bounded in a radial direction by an inner vane shroud and an outer vane shroud and bounded in a circumferential direction by a trailing edge of the leading vane and a projected co-planar line on a convex surface of the adjacent following vane,

• the device comprising:
• fixture means for holding the vane ring in an imaging position wherein the periphery of a selected individual throat is within an optical measuring field of view;
• a primary radiation source disposed in a throat defining position wherein an area of shadow is cast by said primary radiation source on the vane ring initiating in the plane of the selected throat, said area of shadow being surrounded by an area of reflectance;
• radiation detector means for capturing an image of a portion of the vane ring within the field of view;
• and
• image analyzing means for analyzing the image to acquire a dimensional data of a dark portion of the image proportional to an individual throat area of the selected throat.

A method of optically measuring throat area of a gas turbine engine vane ring, the vane ring having an annular array of vanes defining a plurality of throats between adjacent leading and following vanes of the array, each said throat being a planar opening with a periphery bounded in a radial direction by an inner vane shroud and an outer vane shroud and bounded in a circumferential direction by a trailing edge of the leading vane and a projected co-planar line on a convex surface of the adjacent following vane, the method comprising the steps of:

• using a fixture to position a selected throat of the vane ring in an imaging position;
• radiating light onto the vane ring to define the selected throat as an area of reflectance surrounding an area of shadow;
• capturing at least one image of the selected throat;
• and
• analyzing the image to acquire dimensional data of a dark portion of the image proportional to a throat area of the selected throat.

A device for optically measuring throat area in a vane ring for a gas turbine engine, the vane ring having an annular array of vanes defining a plurality of individual throats between adjacent leading and following vanes of the array, each said individual throat being a planar opening with a periphery bounded in a radial direction by an inner vane shroud and an outer vane shroud and bounded in a circumferential direction by a trailing edge of the leading vane and a projected co-planar line on a convex surface of the adjacent following vane, the device comprising:

• a fixture adapted to hold the vane ring in an imaging position wherein the periphery of a selected individual throat is within an optical measuring field of view;
• p‘radiation means disposed in a throat defining position for illuminating the vane ring such that an area of reflectance bounds an area of shadow on the vane assembly which thereby visually delineates a throat area of the selected throat;
• a radiation detecting apparatus for capturing at least one image of a the vane ring within the field of view;
• and
• an image analyzing apparatus for analyzing the at least one image to acquire a dimensional data of a dark portion of the image proportional to the throat area of the selected throat.

A device for optically measuring throat area in a vane ring for a gas turbine engine, the vane ring having an annular array of vanes defining a plurality of individual throats between adjacent leading and following vanes of the array, each said individual throat being a planar opening with a periphery bounded in a radial direction by an inner vane shroud and an outer vane shroud and bounded in a circumferential direction by a trailing edge of the leading vane and a projected line on a convex surface of the adjacent following vane, the line co-planar with the planar opening, the device comprising:

• at least one camera having a field of view;
• a fixture adapted to position a selected throat in an imaging position such that the periphery of the throat is within the field of view of the camera;
• a first radiation source positioned to cast collimated light on the vane ring to delineate the selected throat as an area of reflectance surrounding a shadow area;
• a second radiation source positioned to cast collimated light on said trailing edge;
• and
• an apparatus adapted to receive at least one image of the throat area from the camera and acquire therefrom dimensional data of a dark area of the image representative of the throat area.

A device for optically measuring a throat area defined between adjacent vanes of an annular vane array, the throat area having a planar opening defined by an inner shroud, an outer shroud, a trailing edge of one of the adjacent vanes and a line projected onto a convex surface of the other of the adjacent vanes, the line being co-planar with the throat opening, the device comprising;

• at least one optical radiation detector having a field of view;
• a fixture adapted to position the vane array in an imaging position such that the periphery of the throat is within the field of view of the optical radiation detector;
• at least two radiation sources positioned to radiate light on the vane array to visually delineate the throat area with an area of reflectance surrounding a shadow area corresponding to the opening of the throat area;
• an apparatus adapted tO receive at least one image of the throat area from the optical radiation detector and acquire therefrom dimensional data of a dark portion of the image representative of the throat area.