FIELD: physics.
SUBSTANCE: apparatus for determining distance (Δx) between at least one moving blade and the wall of a gas turbine surrounding at least one moving blade has a waveguide for directing electromagnetic waves and electromagnetic wave radiation through at least one waveguide opening facing the moving blade in the direction of the moving blade. At least one apparatus for inputting electromagnetic waves into the waveguide. At least one apparatus for receiving reflected components electromagnetic waves input into the waveguide. The apparatus also has an evaluation unit for evaluating the received reflected components of input electromagnetic waves, comprising apparatus for comparing the phase of the input electromagnetic waves with the phase of the reflected components of the input electromagnetic waves. Using the evaluation unit, the phase comparison value can be determined for each frequency and the distance (Δx) can be determined by comparing phase comparison values. The waveguide consists of at least two segments which are made from different materials, where heat resistance and attenuation property for electromagnetic waves for the materials, starting from the segment which is connected to input and reception apparatus, increase in the direction of the segment having a waveguide opening.
EFFECT: high measurement accuracy and possibility of directing electromagnetic waves with low attenuation, providing high-temperature resistance.
10 cl, 4 dwg
