Infrared pyrometer for measuring turbine blade temperatures

The design, principles of operation and performance characteristics of a remote-controlled high-resolution infrared pyrometer for mapping the surface temperatures of turbine rotor blades are described. An InAs-detector with a transmission band from 1 Hz to 500 kHz, cooled down to -40 C can obtain a response time of the order of 1 microsec. With detection minimum below 50 C, the smallest detectable temperature variation of 5 C, and the resolving power on the blade surface of 2 sq mm, the device offers significant advantages over the conventional thermocouple techniques. Endoscoping sighting is carried out by means of a reflection optics (including a molten SiO2 total reflection prism) mounted in a cooled, remote-controlled tube, capable of sustaining temperatures up to 1350 C and pressures up to 3 bar.