In-flight engine control optical pyrometer

Claim 1

An in-flight engine control optical pyrometer for measuring the temperature of a turbine blade in a jet engine, comprising: optical probe means positioned in the jet engine so as to gather from the turbine blade an optical beam having a spectral width and having an emitted component from the turbine blade and a reflected component from a fireball having an equivalent black body temperature, said optical probe means includes sight tube means having an inner bore adapted to receive said turbine blade optical beam and positioning an optical guide means therein, said sight tube means further including shutter means responsive to said jet engine air pressure, positioned in said sight tube means and providing said turbine blade optical beam to said optical guide means only above a threshold magnitude of said air pressure; optical detection module means, including housing means adapted to receive the optical guide means; first photodetector means contained within said housing means absorbing from the turbine blade optical beam a first optical component having a first spectral width selected to be a portion of the target beam spectral width and passing a remainder optical beam therethrough, said first photodetector means providing an electrical signal equivalent of said first optical component; second photodetector means contained within said housing means receiving said remainder optical beam and providing an electrical signal equivalent thereof; and signal processing means receiving said first and second signals and further receiving energy ratio signals, for providing reflection corrected energy signals from the difference between said first signals and the product of said energy ratio signals and said second signal.