Positioning device for an optical triangulation sensor
AssigneeThird Dimension Software Limited
InventorTim Monks
Life of this patent
Estimating the term…
Abstract
A tool or attachment jig for mounting an optical triangulation sensor on a turbine blade in a position to measure the gap between the distal tip of the turbine blade and the adjacent shroud. The tool includes a device for indicating the orientation of the sensor. This means that the tool can match a measurement from the optical triangulation sensor with a position on the circumference of the shroud. By taking a plurality of measurements as the turbine blade is rotated with respect to the annular casing, an angular profile for the gap between the turbine blade and the casing can be obtained in a much quicker and more efficient way than a conventional system.
Claims15
A positioning device for locating a planar light beam emitted by an optical triangulation sensor across the radial gap between a distal edge of a turbine blade and the inner surface of an annular casing in which the turbine blade is rotatably mounted, the positioning device comprising:
- an attachment device mounting on the turbine blade, the attachment device comprising a frame supporting an optical triangulation sensor in a fixed position relative to the attachment device;
- and
- an orientation sensing device mounted on the attachment device, the orientation sensing device being arranged to detect an orientation with respect to the direction in which gravity acts, wherein the attachment device includes a shaped retention profile adapted to mate with the turbine blade at a fixed radial position thereon.
A method for measuring the radial gap between a distal edge of a turbine blade and the inner surface of an annular casing in which the turbine blade is rotatably mounted, the method comprising:
- mounting an optical triangulation sensor in a fixed radial position on the turbine blade, wherein the optical triangulation sensor is mounted on the turbine blade using a positioning device that comprises:
- an attachment device mounted on the turbine blade, the attachment device comprising a frame that supports the optical triangulation sensor in a fixed position relative to the attachment device, wherein the attachment device includes a shaped retention profile adapted to mate with the turbine blade at a fixed radial position thereon;
- and
- an orientation sensing device arranged to detect an orientation with respect to the direction in which gravity acts;
- emitting a planar beam of light from the optical triangulation towards the distal edge of the turbine blade, so that the planar beam of light intersects the turbine blade and the inner surface of the annular casing in a line that spans a radial gap between the distal edge of the turbine blade and the inner surface of the annular casing;
- rotating the turbine blade relative to the annular casing;
- capturing a plurality of images of the line that spans the radial gap between the distal edge and the inner surface of the annular casing;
- and
- detecting an angular position of the turbine blade within the annular casing for each of the plurality of images.
Dependencies are inferred from the claim text.