Stepped Fixed Mirror System
Where blade heights are larger, for example in power turbines, then a greater scan range is required. Replacing the small pneumatic actuator with a modified Rotadata traverse actuator provides the increased range of movement required. A fixed mirror sight tube similar to, but longer than, that of the pneumatic system, is mounted in the actuator.
The Rotadata traverse actuators have proven their reliability with over 30 years of service with many major engine manufacturers. The actuator uses a stepper motor to drive the sight tube to view any blade height within its range. Sight tubes can be interchanged to provide a variety of scanning capabilities.
The sight tube is driven to a set of pre-defined blade heights. At each scan position, a set of data is collected over a number of engine revolutions. As the blades rotate, the viewing area moves across the blade. If the scan positions are close enough together for the target spots to overlap, then a continuous area is covered. If the scan positions are further apart, then a 'striped' area is covered.
Platform Scanner System
In addition to measuring temperatures on the surface of the blade airfoil, the blade platform temperature profile can be of interest. A much steeper viewing angle is required to read from the blade platform and this is achieved by replacing the mirror in the end of the sight tube with a prism. The sight tube is mounted in a modified Rotadata traverse actuator with both linear and rotary drives to provide the nescessary positioning capabilities.
Sight tubes can be interchanged to provide a variety of scanning capabilities. By changing between prism and mirror sight tubes, the dual axis actuator can be used to perform platform or blade scanning as required.
The viewing angle is determined by the prism angle. The sight tube is inserted into the gas stream to a pre-defined depth to perform the scan. The sight tube is then rotated through a set of angles corresponding to positions along the platform. At each position, a set of data is collected over a number of engine revolutions. Probe rotation combined with blade movement gives the scan area.
The Rotadata Traverse Mounted Fixed Mirror package includes:
- Preliminary evaluation stage to determine optimal solution
- 3D heat mapping, gas flow analysis and heat transfer analysis
- Probe design to meet environmental requirements
- Probe calibration
- Supply of calibration equipment, training and tools
- Design and supply of engine interface parts
- System hardware production and supply
- Supply of system software for actuator control and data acquisition and processing
- Training in system use at Rotadata or on customer site
- Support during system installation
- Support during engine testing
- Data processing support