TURBINE OPTICAL PYROMETRY
Electronically Traversed Mirror

Blade Scanning 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 specialised Rotadata probe traversing actuator provides the increased range of movement required. A fixed mirror probe similar to, but longer than, that of the pneumatic system, is mounted in the actuator.

The Rotadata probe traversing actuators have proven their reliability with over 30 years of service with many major engine manufacturers. The actuator can traverse the probe to view any blade height within its range.

Probes can be interchanged to provide a variety of scanning capabilities. The probe 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.

Platform Scanning 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 probe with a prism. The probe is mounted in a specialised Rotadata probe traversing actuator with both linear and rotary drives to provide the necessary positioning capabilities.

Probes can be interchanged to provide a variety of scanning capabilities. By changing between prism and mirror probes, 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 probe is inserted into the gas stream to a pre-defined depth to perform the scan. The probe 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.