TURBINE OPTICAL PYROMETRY
Pneumatically Traversed Mirror System

The Pneumatically Traversed Fixed Mirror System is the most commonly used Pyrometry system used to scan over a range of areas on the blade surfaces with temperatures of up to 1400℃.

A pyrometer probe with a fixed viewing angle is mounted in a pneumatic actuator. The probe diameter is minimised enabling where practical standard borescope holes to be used. The pyrometer probe can be easily removed from the actuator allowing switching between probes with different viewing angles.

The maximum scan depth is determined by the ability of the probe to withstand the physical and thermal stresses encountered in the gas stream. The fixed mirror angle is set to view within the required blade height range. Data is collected continuously while the pneumatic drive inserts and retracts the probe. As the pyrometer probe is inserted, the viewing area moves down the blade.

Scans can be performed in less than 20 seconds which result in high resolution 2 dimensional thermal maps. These thermal maps are frequently used by OEMs for their verification and validation programmes.